Articles de revues : « Novel Oxides - Structural Properties »

1

Bai, Shuiquan. « A Research of Selective Catalytic Reduction of NOx with NH3 by Using Novel Catalysts ». Journal of Physics : Conference Series 2539, n^o 1 (1 juillet 2023) : 012058. http://dx.doi.org/10.1088/1742-6596/2539/1/012058.

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Abstract Nitrogen oxides are one of the most important industrial pollutants, which have many harmful effects on the human body and the environment. In this paper, the formation mechanism of nitrogen oxides was studied, and the selective catalytic reduction of nitrogen oxides was carried out by selective catalytic reduction technology. This paper also reviews the low-temperature denitration performance of molecular sieve catalysts, manganese oxide and ceria-based catalysts, and expounds on the influence of catalysts on denitration activity under different active components. It is found that ceria-based catalytic materials have better structural properties and catalytic performance, the methods to improve the performance of ceria-based catalysts are discussed, and the future development of ceria-based catalysts has been prospected.

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Nnadozie, Ebenezer C., et Peter A. Ajibade. « Multifunctional Magnetic Oxide Nanoparticle (MNP) Core-Shell : Review of Synthesis, Structural Studies and Application for Wastewater Treatment ». Molecules 25, n^o 18 (9 septembre 2020) : 4110. http://dx.doi.org/10.3390/molecules25184110.

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The demand for water is predicted to increase significantly over the coming decades; thus, there is a need to develop an inclusive wastewater decontaminator for the effective management and conservation of water. Magnetic oxide nanocomposites have great potentials as global and novel remediators for wastewater treatment, with robust environmental and economic gains. Environment-responsive nanocomposites would offer wide flexibility to harvest and utilize massive untapped natural energy sources to drive a green economy in tandem with the United Nations Sustainable Development Goals. Recent attempts to engineer smart magnetic oxide nanocomposites for wastewater treatment has been reported by several researchers. However, the magnetic properties of superparamagnetic nanocomposite materials and their adsorption properties nexus as fundamental to the design of recyclable nanomaterials are desirable for industrial application. The potentials of facile magnetic recovery, ease of functionalization, reusability, solar responsiveness, biocompatibility and ergonomic design promote the application of magnetic oxide nanocomposites in wastewater treatment. The review makes a holistic attempt to explore magnetic oxide nanocomposites for wastewater treatment; futuristic smart magnetic oxides as an elixir to global water scarcity is expounded. Desirable adsorption parameters and properties of magnetic oxides nanocomposites are explored while considering their fate in biological and environmental media.

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Lorenz, Michael. « Pulsed laser deposition of functional oxides - towards a transparent electronics ». Acta Crystallographica Section A Foundations and Advances 70, a1 (5 août 2014) : C1412. http://dx.doi.org/10.1107/s2053273314085878.

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Metal oxides, in particular with transition metals, show strong electronic correlations which determine a huge variety of electronic properties, together with other functionalities. For example, ZnO and Ga2O3 as wide-bandgap semiconductors have a high application potential as transparent functional layers in future oxide electronics [1-2]. Other oxides of current interest are ferrimagnetic spinels of the type MFe2O4 (M=Zn,Co,Ni), see K. Brachwitz et al. Appl. Phys. Lett. 102, 172104 (2013), or highly correlated iridate films, see M. Jenderka et al. Phys. Rev. B 88, 045111 (2013). Furthermore, combinations of ferroelectric and magnetic oxides in multiferroic composites and multilayers show promising magnetoelectric coupling. For the exploratory growth of the above mentioned novel oxides into nm-thin films, pulsed laser deposition (PLD) appears as the method of choice because of its extremely high flexibility in terms of material and growth conditions, high growth rate and excellent structural properties [3]. This talk highlights recent developments of new functional oxides using unique large-area PLD processes running for more than two decades in the lab of the author [3].

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Wang, Yu, F. Zhang, L. Z. Qi, L. Wang et L. C. Cheng. « The Preparation and Properties of New Silver-Metal Oxide Graded Composite Electrical Contact Materials ». Key Engineering Materials 280-283 (février 2007) : 1917–20. http://dx.doi.org/10.4028/www.scientific.net/kem.280-283.1917.

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Electrical contact material is a very important material for the electric power industry. An electrical contact material should display good structural characteristics (suitable hardness, high thermal conductivity and stabilization) as well as a good functional characteristic (low electrical resistivity). It is difficult to fabricate such a contact material with all these good performing parameters by common techniques because these physical parameters influence each other. In this paper, we report a novel investigation to design and prepare silver-metal oxide composite materials according to functionally layered and graded material (FLGM) concept and meeting requirement as electrical contact material. The silver-based composite samples characterized by layered component were prepared with conventional solid-phase sintering technique. One kind of sample consists of tin dioxide and silver material, in which SnO2 exhibits a graded distribution. Another consists of two metal oxides, cadmium and zinc oxides, and silver material, in which each layer has different metal oxide. Hardness, thermal conductivity and electrical conductivity, were measured and related problems are discussed. Especially, welding resistance as an important parameter for practical application was tested. SEM analyses before and after electrical erosion were also performed. We conclude that the functionally graded material (FGM) concept as a novel designing and fabricating method has potential for electrical contact composite material.

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LU, HUI, et YAN ZHANG. « A NOVEL Ba/Nb CO-DOPED (Ba0.15Sr0.85)(Nb0.15Co0.85)O3–δ OXIDE AS AN OXYGEN ADSORBENT : STRUCTURAL AND OXYGEN SORPTION PROPERTIES ». Functional Materials Letters 03, n^o 04 (décembre 2010) : 275–78. http://dx.doi.org/10.1142/s1793604710001408.

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The novel Ba/Nb co-doped (Ba0.15Sr0.85)(Nb0.15Co0.85)O3–δ oxide was synthesized by the solid-state reaction method. The (Ba0.15Sr0.85)(Nb0.15Co0.85)O3–δ oxide was studied by X-ray diffraction (XRD), differential thermal analysis (DTA) and thermogravimetry (TG). The results demonstrate that the structural stability of the Ba/Nb co-doped (Ba0.15Sr0.85)(Nb0.15Co0.85)O3–δ was improved significantly compared to that of the Ba -doped SrCoO3–δ , in which a phase transformation occurred during the heating process. The incorporation of Nb5+ in the SrCoO3–δ -based oxides can significantly stabilize the neighboring oxygen octahedral, resulting in the improved stability of the (Ba0.15Sr0.85)(Nb0.15Co0.85)O3–δ . The oxygen sorption properties of (Ba0.15Sr0.85)(Nb0.15Co0.85)O3–δ between 300°C and 950°C in air were investigated, and a high sorption capacity of 9.45 mL O2 (STP)/g oxide was obtained.

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Huang, Jin Hua, Rui Qin Tan, Jia Li, Yu Long Zhang, Ye Yang et Wei Jie Song. « Thermal Stability of Aluminum Doped Zinc Oxide Thin Films ». Materials Science Forum 685 (juin 2011) : 147–51. http://dx.doi.org/10.4028/www.scientific.net/msf.685.147.

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Transparent conductive oxides are key electrode materials for thin film solar cells. Aluminum doped zinc oxide has become one of the most promising transparent conductive oxide (TCO) materials because of its excellent optical and electrical properties. In this work, aluminum doped zinc oxide thin films were prepared using RF magnetron sputtering of a 4 at% ceramic target. The thermal stability of aluminum doped zinc oxide thin films was studied using various physical and structural characterization methods. It was observed that the electrical conductivity of aluminum doped zinc oxide thin films deteriorated rapidly and unevenly when it was heated up to 350 °C. When the aluminum doped zinc oxide thin films were exposed to UV ozone for a short time before heating up, its thermal stability and large area homogeneity were significantly improved. The present work provided a novel method for improving the durability of aluminum doped zinc oxides as transparent conductive electrodes in thin film solar cells.

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Nagpal, D., V. Gajraj, A. Kumar, K. I. Gnanasekar et C. R. Mariappan. « Novel compositions of mesoporous spinel-type ternary metal oxides microspheres : Structural and electrical properties functionality ». Physica B : Condensed Matter 630 (avril 2022) : 413679. http://dx.doi.org/10.1016/j.physb.2022.413679.

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Nha Khanh, Dang Nguyen, Nguyen Thi Mai Tho, Nguyen Quoc Thang, Nguyen Thanh Tien, Chau Tan Phong, Mai Quynh Cang et Nguyen Thi Kim Phuong. « VISIBLE-LIGHT DEGRADATION OF INDIGO CARMINE USING A NOVEL MIXED METAL OXIDES/REDUCED GRAPHENE OXIDE HYBRID CATALYSTS ». Vietnam Journal of Science and Technology 57, n^o 5 (8 octobre 2019) : 572. http://dx.doi.org/10.15625/2525-2518/57/5/13676.

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A novel ZnBi2O4/rGO hybrid catalysts had been synthesized by a simple precipitation method. The crystallinity, structural, and morphological features were studied by XRD, FE-SEM and UV-Vis diffused reflectance techniques. The photocatalytic activity of ZnBi2O4/rGO catalysts were evaluated by degradation of Indigo Carmine dye under visible-light irradiation. The enhancement of photocatalytic properties of ZnBi2O4/rGO attributed to the synergistic effect between ZnBi2O4 and rGO, which effectively separation of the photogenerated electron-hole pairs in ZnBi2O4. Moreover, the obtained ZnBi2O4/rGO displayed high chemical stability after four consecutive experiments under visible light.

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Tsyshevsky, Roman V., Sergey N. Rashkeev et Maija M. Kuklja. « Control of Explosive Chemical Reactions by Optical Excitations : Defect-Induced Decomposition of Trinitrotoluene at Metal Oxide Surfaces ». Molecules 28, n^o 3 (18 janvier 2023) : 953. http://dx.doi.org/10.3390/molecules28030953.

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Interfaces formed by high energy density materials and metal oxides present intriguing new opportunities for a large set of novel applications that depend on the control of the energy release and initiation of explosive chemical reactions. We studied the role of structural defects at a MgO surface in the modification of electronic and optical properties of the energetic material TNT (2-methyl-1,3,5-trinitrobenzene, also known as trinitrotoluene, C7H5N3O6) deposited at the surface. Using density functional theory (DFT)-based solid-state periodic calculations with hybrid density functionals, we show how the control of chemical explosive reactions can be achieved by tuning the electronic structure of energetic compound at an interface with oxides. The presence of defects at the oxide surface, such as steps, kinks, corners, and oxygen vacancies, significantly affects interfacial properties and modifies electronic spectra and charge transfer dynamics between the oxide surface and adsorbed energetic material. As a result, the electronic and optical properties of trinitrotoluene, mixed with an inorganic material (thus forming a composite), can be manipulated with high precision by interactions between TNT and the inorganic material at composite interfaces, namely, by charge transfer and band alignment. Also, the electron charge transfer between TNT and MgO surface reduces the decomposition barriers of the energetic material. In particular, it is shown that surface structural defects are critically important in the photodecomposition processes. These results open new possibilities for the rather precise control over the decomposition initiation mechanisms in energetic materials by optical excitations.

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Cotell, Catherine M., et Kenneth S. Grabowski. « Novel Materials Applications of Pulsed Laser Deposition ». MRS Bulletin 17, n^o 2 (février 1992) : 44–53. http://dx.doi.org/10.1557/s0883769400040616.

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The successful use of pulsed laser deposition (PLD) to fabricate thin film superconductors has generated interest in using the technique to deposit thin films of other materials. The compositional fidelity between laser target and deposited film and the ability to deposit films in reactive gas environments make the PLD process particularly well suited to the deposition of complex multicomponent materials. Cheung and Sankur recently provided an excellent review of the PLD field, including a table of over 100 elements, inorganic and organic compounds, andsuperlattices that have been laser evaporated. Over 75 of these materials were deposited as thin films.The goal of this article is to provide an introduction to some of the newer applications of PLD for thin film fabrication. Four classes of materials are highlighted: ferroelectrics, bioceramics, ferrites, and tribological materials. Ferroelectric materials are structurally related to the high-temperature superconducting oxides and therefore are a direct extension of the recent superconducting oxide work. Bioceramics are dissimilar in structure and application to both ferroelectrics and superconducting oxides, but they are complex multicomponent oxides and, therefore, benefit from the use of PLD. Ferrites, also complex, multicomponent oxides, represent another exciting, but only lightly explored opportunity for PLD. In contrast, tribological materials are typically neither complex nor multicomponent. Nevertheless, interesting structures and properties have been produced by PLD. A few of the more important ones will be discussed. These different types of materials demonstrate the diversity of capabilities offered by PLD.

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TERESITA, V. MARY, V. JESEENTHARANI, B. AVILA JOSEPHINE et S. ARUL ANTONY. « SYNTHESIS OF NOVEL NANOSTRUCTURED LANTHANUM COBALT FERRITE MIXED METAL OXIDES BY SOL–GEL ». International Journal of Nanoscience 12, n^o 01 (février 2013) : 1350007. http://dx.doi.org/10.1142/s0219581x13500075.

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Properties of nanoscale materials are very interesting and these are either comparable to or superior to those of bulk. These materials are interesting due to their exciting size dependent optical, electronic, magnetic, thermal, mechanical and chemical properties. Different mole ratios of nanostructured mixed metal oxides of LaCo x Fe 1-x O 3-δ (x = 0 to 1) were prepared by the sol–gel method by varying the mole ratios of iron and cobalt substrates. The compounds were sintered for 700°C in the tubular furnace for 8 h. The purity of the compounds was analyzed by TG-DTA. The compounds were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM) studies were employed to study the structural phases, vibrational frequencies, surface morphology of the highest humidity sensing compounds.

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Jayaram, Peediyekkal, T. P. Jaya et P. P. Pradyumnan. « Bulk Synthesis and Structural Determination of High Mobility Multication Transparent Conducting Oxides ». Solid State Phenomena 194 (novembre 2012) : 124–28. http://dx.doi.org/10.4028/www.scientific.net/ssp.194.124.

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This work reports the synthesis of novel quaternary transparent conducting oxide Cd(1-x)Sn(1-x)InxGaxO3( x=0.1, 0.2, 0.3) at 1225°C via solid state reaction route. The investigations on structural, optical and electrical properties have been carried out. Powder X-ray diffraction revealed the phase purity and distorted orthorhombic structure of the species synthesized. Distortion of the structure is due to the substitution of In3+and Ga3+in CdSnO3 (JCPDS card no.340885) matrix. The optical transmittance approximated by the reflectance shows considerable increase in the transmittance of visible light along with the increase of substitution. Typical Burstein-Moss effect is observed with the increase in x value as a variation in optical bandgap from 2.7 to 2.9eV. Four point Hall measurements by Van der-Pauw method exhibit superior properties in charge carrier concentration and mobility. Maximum bulk charge concentration of 4.78x1017 cm-3is obtained for x=0.3. Hall mobility depends on carrier concentration and steeply increases with the carrier concentration. Considerable drop in the resistivity of the material along with higher transmittance is a critical finding in the experiment.

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Alnahari, Hisham, Annas Al-Sharabi, AH Al-Hammadi, Abdel-Basit Al-Odayni et Adnan Alnehia. « Synthesis of glycine-mediated CuO–Fe₂O₃–MgO nanocomposites : Structural, optical, and antibacterial properties ». Composites and Advanced Materials 32 (15 mai 2023) : 263498332311768. http://dx.doi.org/10.1177/26349833231176838.

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Multi-phase metal oxides nanocomposites (NCs) have attracted considerable attention due to their extraordinary properties and novel applications over monometallic ones. Hence, trimetallic oxides nanoparticles (NPs) are preferred because of their immensely improved optical, catalytic, and biological properties, but few materials have been reported. Besides, glycine is an excellent structure-directing agent for NPs production with tailored physicochemical properties. Thus, in this work, a novel tri-phase CuO–Fe2O3–MgO (1:1:1) NCs was prepared via a sol-gel method in the presence of glycine as a fuel. The obtained NCs were characterized by Fourier transmission infrared, X-ray diffraction (XRD), Scanning electron micrographs, and UV-Vis. The XRD analysis emphasized the formation of NCs with monoclinic CuO, cubic MgO, hexagonal Fe2O3, and tetragonal CuFe2O4 crystals. The average crystallite size (D) was in the order of 10th of nm as computed by Scherrer method, with ternary phase seemingly affect the straightforward influence of glycine fuel concentration on the final crystallite sizes. UV-Vis analysis indicates two optical energy bandgaps which increased as glycine concentration increase. The antibacterial test against Staphylococcus aureus and Escherichia coli bacteria revealed comparable activity to that of Azithromycin standard drug, which increased with glycine concentration increase. The glycine-based tailored structural, optical, and biological properties of such trimetallic NCs making them of considerable candidate for certain applications development, possibly electronics and antibiotics; a case that encourage further investigations.

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AMIN, N., M. AKHTAR, M. SABIR, K. MAHMOOD, A. ALI, G. MUSTAFA, M. S. HASAN et al. « SYNTHESIS, STRUCTURAL AND OPTICAL PROPERTIES OF Zn-SUBSTITUTED Co W-FERRITES BY COPRECIPITATION METHOD ». Journal of Ovonic Research 16, n^o 1 (janvier 2020) : 11–19. http://dx.doi.org/10.15251/jor.2020.161.11.

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A series W-type BaMe2Fe16O27 ferrites withcomposition BaZnxCo1-xFe16O27(x ═ 0.0, 0.1, 0.2, 0.3, 0.4 &0.5) were manufactured by co-precipitation method sintering at 1100°C for 8 h. XRD, FTIR, SEM, UV-vis and I-V techniques were applied to investigate structural, optical, morphological and electrical properties respectively. Crystallite size was observed in the range of (37.58 nm- 54.75 nm) revealed by XRD and was confirmed by SEM analysis. IR exposed the existence of metal oxides (M -O). Optical band gap was in (3.0 eV- 5.2 eV) range which proved the trend of DC resistivity in increasing trend. Activation energy discovered the conversion of ferrimagnetism to paramagnetism characteristics confirming the W-type materials are highly suitable for novel application.

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Chen, Dongxia, Ying Zhang, Xianghong Ge, Yongguang Cheng, Yayun Liu, Huanli Yuan, Juan Guo, Mingju Chao et Erjun Liang. « Structural, vibrational and thermal expansion properties of Sc2W4O15 ». Physical Chemistry Chemical Physics 20, n^o 30 (2018) : 20160–66. http://dx.doi.org/10.1039/c8cp02403k.

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A novel oxide material with the formula of Sc₂W₄O₁₅and orthorhombic symmetry is synthesized by solid state reactions and its structure, composition, vibrational properties and thermal expansion are investigated and identified by several means.

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Pandey, R. K., H. Stern, W. J. Geerts, P. Padmini, P. Kale, Jian Dou et R. Schad. « Room Temperature Magnetic-Semicondcutors in Modified Iron Titanates : Their Properties and Potential Microelectronic Devices ». Advances in Science and Technology 54 (septembre 2008) : 216–22. http://dx.doi.org/10.4028/www.scientific.net/ast.54.216.

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The phenomenal growths of information technology and related fields have warranted the development of new class of materials. Multifunctional oxides, magnetic-semiconductors, multiferroics and smart materials are just a few examples of such materials. They are needed for the development of novel technologies such as spintronics, magneto-electronics, radhard electronics, and advanced microelectronics. For these technologies, of particular interest are some solid solutions of ilmenite-hematite (IH) represented by (1-x) FeTiO3.xFe2O3 where x varies from 0 to 1; Mn-doped ilmenite (Mn+3-FeTiO3) and Mn-doped pseudobrookite, Mn+3-Fe2TiO5 (PsB). These multifunctional oxides are ferromagnetic with the magnetic Curie points well above the room temperature as well as wide bandgap semiconductors with band gap Eg > 2.5 eV. This paper outlines: (a) processing of device quality samples for structural, electrical and magnetic characterization, (b) fabrication and evaluation of an integrated structure for controlled magnetic switching, and (c) the response of the two terminal non-linear current-voltage (I-V) characteristics when biased by a dc voltage. Subsequently, we will identify a few microelectronic applications based on this class of oxides.

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Ganesh, Vanga, Thekrayat H. AlAbdulaal, Manal AlShadidi, Mai S. A. Hussien, Abdelfatteh Bouzidi, Hamed Algarni, Heba Y. Zahran et al. « Enhancement in the Structural, Electrical, Optical, and Photocatalytic Properties of La2O3-Doped ZnO Nanostructures ». Materials 15, n^o 19 (2 octobre 2022) : 6866. http://dx.doi.org/10.3390/ma15196866.

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A lanthanum oxide (La2O3)-ZnO nanostructured material was synthesized in the proposed study with different La2O3 concentrations, 0.001 g to 5 g (named So to S7), using the combustion method. X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transformation infrared spectroscopy (FT-IR) were utilized for investigating the structure, morphology, and spectral studies of the La2O3- ZnO nanomaterials, respectively. The results obtained from previous techniques support ZnO’s growth from crystalline to nanoparticles’ fine structure by changing the concentrations of lanthanum oxide (La2O3) dopants in the host matrix. The percentage of ZnO doped with La- influences the ZnO photocatalytic activity. SEM analysis confirmed the grain size ranged between 81 and 138 nm. Furthermore, UV-Vis diffuse reflectance spectroscopy was performed to verify the effects of La2O3 dopants on the linear optical properties of the nano-composite oxides. There was a variation in the energy bandgaps of La2O3-ZnO nanocomposites, increasing the weight concentrations of lanthanum dopants. The AC electrical conductivity, dielectric properties, and current–voltage properties support the enactment of the electrical characteristics of the ZnO nanoparticles by adding La2O3. All the samples under investigation were used for photodegradation with Rhodamine B (RhB) and Methylene Blue (MB). In less than 30 min of visible light irradiation, S4 (0.5 g) La2O3-ZnO reached 99% of RhB and MB degradation activity. This study showed the best photocatalytic effect for RhB and MB degradation of 0.13 and 0.11 min−1 by 0.5 g La2O3-ZnO. Recycling was performed five times for the nanocatalysts that displayed up to 98 percent catalytic efficiency for RhB and MB degradation in 30 min. The prepared La2O3-ZnO nanostructured composites are considered novel candidates for various applications in biomedical and photocatalytic studies.

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Tohyama, Takenori, Takashi Saito et Yuichi Shimakawa. « Material Design, Synthesis, Measurements of Structural and Physical Properties, and Electronic Structure Calculation of New Functional Oxides : Novel A-site Ordered Perovskite Structure Oxides ». Journal of the Japan Society of Powder and Powder Metallurgy 57, n^o 12 (2010) : 779–85. http://dx.doi.org/10.2497/jjspm.57.779.

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Liyanage, Laalitha S. I., Jagoda Sławińska, Priya Gopal, Stefano Curtarolo, Marco Fornari et Marco Buongiorno Nardelli. « High-Throughput Computational Search for Half-Metallic Oxides ». Molecules 25, n^o 9 (25 avril 2020) : 2010. http://dx.doi.org/10.3390/molecules25092010.

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Half metals are a peculiar class of ferromagnets that have a metallic density of states at the Fermi level in one spin channel and simultaneous semiconducting or insulating properties in the opposite one. Even though they are very desirable for spintronics applications, identification of robust half-metallic materials is by no means an easy task. Because their unusual electronic structures emerge from subtleties in the hybridization of the orbitals, there is no simple rule which permits to select a priori suitable candidate materials. Here, we have conducted a high-throughput computational search for half-metallic compounds. The analysis of calculated electronic properties of thousands of materials from the inorganic crystal structure database allowed us to identify potential half metals. Remarkably, we have found over two-hundred strong half-metallic oxides; several of them have never been reported before. Considering the fact that oxides represent an important class of prospective spintronics materials, we have discussed them in further detail. In particular, they have been classified in different families based on the number of elements, structural formula, and distribution of density of states in the spin channels. We are convinced that such a framework can help to design rules for the exploration of a vaster chemical space and enable the discovery of novel half-metallic oxides with properties on demand.

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Černý, Radovan, et Pascal Schouwink. « The crystal chemistry of inorganic metal borohydrides and their relation to metal oxides ». Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 71, n^o 6 (1 décembre 2015) : 619–40. http://dx.doi.org/10.1107/s2052520615018508.

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The crystal structures of inorganic homoleptic metal borohydrides are analysed with respect to their structural prototypes found amongst metal oxides in the inorganic databases such as Pearson's Crystal Data [Villars & Cenzual (2015). Pearson's Crystal Data. Crystal Structure Database for Inorganic Compounds, Release 2014/2015, ASM International, Materials Park, Ohio, USA]. The coordination polyhedra around the cations and the borohydride anion are determined, and constitute the basis of the structural systematics underlying metal borohydride chemistry in various frameworks and variants of ionic packing, including complex anions and the packing of neutral molecules in the crystal. Underlying nets are determined by topology analysis using the program TOPOS [Blatov (2006). IUCr CompComm. Newsl. 7, 4–38]. It is found that the Pauling rules for ionic crystals apply to all non-molecular borohydride crystal structures, and that the latter can often be derived by simple deformation of the close-packed anionic lattices c.c.p. and h.c.p., by partially removing anions and filling tetrahedral or octahedral sites. The deviation from an ideal close packing is facilitated in metal borohydrides with respect to the oxide due to geometrical and electronic considerations of the BH4 − anion (tetrahedral shape, polarizability). This review on crystal chemistry of borohydrides and their similarity to oxides is a contribution which should serve materials engineers as a roadmap to design new materials, synthetic chemists in their search for promising compounds to be prepared, and materials scientists in understanding the properties of novel materials.

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García-Fernández, Javier, Almudena Torres-Pardo, Julio Ramírez-Castellanos, Marta D. Rossell et José M. González-Calbet. « Evaluation of the Nanodomain Structure in In-Zn-O Transparent Conductors ». Nanomaterials 11, n^o 1 (14 janvier 2021) : 198. http://dx.doi.org/10.3390/nano11010198.

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The optimization of novel transparent conductive oxides (TCOs) implies a better understanding of the role that the dopant plays on the optoelectronic properties of these materials. In this work, we perform a systematic study of the homologous series ZnkIn2Ok+3 (IZO) by characterizing the specific location of indium in the structure that leads to a nanodomain framework to release structural strain. Through a systematic study of different terms of the series, we have been able to observe the influence of the k value in the nano-structural features of this homologous series. The stabilization and visualization of the structural modulation as a function of k is discussed, even in the lowest term of the series (k = 3). The strain fields and atomic displacements in the wurtzite structure as a consequence of the introduction of In3+ are evaluated.

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Kim, Hyun-Joo, Jin Hee Bae, Seonmin Lee, Jinwoo Kim, Samooel Jung, Cheorun Jo, Jin Young Lee, Jung Hyun Seo et Sanghoo Park. « Structural and Functional Changes in Soybean Protein via Remote Plasma Treatments ». Molecules 28, n^o 9 (4 mai 2023) : 3882. http://dx.doi.org/10.3390/molecules28093882.

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To the best of our knowledge, few studies have utilized cold plasma to improve soybean protein extraction yield and the functional properties of soybean protein. In this study, we aimed to assess the benefits of remote plasma treatments on soybean with respect to the utilization of soybean protein. This study involved two different sample forms (whole and crushed beans), two different plasma chemistry modes (ozone and nitrogen oxides [NOx = NO + NO2]), and a novel pressure-swing reactor. Crushed soybeans were significantly affected by NOx-mode plasma treatment. Crushed soybeans treated with NOx-mode plasma had the best outcomes, wherein the protein extraction yield increased from 31.64% in the control to 37.90% after plasma treatment. The water binding capacity (205.50%) and oil absorption capacity (267.67%) of plasma-treated soybeans increased to 190.88% and 246.23 % of the control, respectively. The emulsifying activity and emulsion stability slightly increased compared to those of the control. The secondary structure and surface hydrophobicity were altered. The remote plasma treatment of crushed soybeans increased soybean protein extraction yield compared to plasma-treated whole beans as well as untreated beans and altered the structural and physicochemical properties of soybean proteins.

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Liberka, Michal, Jedrzej Kobylarczyk et Robert Podgajny. « Structural Disorder in High-Spin {CoII9WV6} (Core)-[Pyridine N-Oxides] (Shell) Architectures ». Molecules 25, n^o 2 (8 janvier 2020) : 251. http://dx.doi.org/10.3390/molecules25020251.

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The combinations of Co(II), octacyanidotungstate(V), and monodentate pyridine N-oxide (pyNO) or 4-phenylpyridine N-oxide (4-phpyNO) led to crystallization of novel crystalline phases {CoII[CoII8(pyNO)12(MeOH)12][WV(CN)8]6} (1) and {CoII[CoII8(4-phpyNO)7(MeOH)17][WV(CN)8]6}·7MeOH·(4-phpyNO)3 (2). In both architectures, metal–cyanide clusters are coordinated by N-oxide ligands in a simple monodentate manner to give the spherical objects of over 1 nm core diameter and about 2.2 nm (1) and 3 nm (2) of the total diameter, terminated with the aromatic rings. The supramolecular architecture is dominated by dense and rich π–π interaction systems. Both structures are characterized by a significant structural disorder in ligand shell, described with the suitable probability models. For 1, the π–π interactions between the pyNO ligands attached to the same metal centers are suggested for the first time. In 2, 4-phpyNO acts as monodentate ligand and as the crystallization molecule. Magnetic studies indicate the high-spin ground state due to the ferromagnetic interactions Co(II)–W(V) through the cyanido bridges. Due to the high symmetry of the clusters, no signature of slow magnetic relaxation was observed. The characterization is completed by solid-state IR and UV–Vis–NIR spectroscopy. The conditions for the stable M9M’6-based crystals formation are synthetically discussed in terms of the type of capping ligands: monodentate, bridging, and chelating. The potential of the related polynuclear forms toward the magnetism-based functional properties is critically indicated.

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Lehr, Daniela, Markus R. Wagner, Johanna Flock, Julian S. Reparaz, Clivia M. Sotomayor Torres, Alexander Klaiber, Thomas Dekorsy et Sebastian Polarz. « A single-source precursor route to anisotropic halogen-doped zinc oxide particles as a promising candidate for new transparent conducting oxide materials ». Beilstein Journal of Nanotechnology 6 (18 novembre 2015) : 2161–72. http://dx.doi.org/10.3762/bjnano.6.222.

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Numerous applications in optoelectronics require electrically conducting materials with high optical transparency over the entire visible light range. A solid solution of indium oxide and substantial amounts of tin oxide for electronic doping (ITO) is currently the most prominent example for the class of so-called TCOs (transparent conducting oxides). Due to the limited, natural occurrence of indium and its steadily increasing price, it is highly desired to identify materials alternatives containing highly abundant chemical elements. The doping of other metal oxides (e.g., zinc oxide, ZnO) is a promising approach, but two problems can be identified. Phase separation might occur at the required high concentration of the doping element, and for successful electronic modification it is mandatory that the introduced heteroelement occupies a defined position in the lattice of the host material. In the case of ZnO, most attention has been attributed so far to n-doping via substitution of Zn2+ by other metals (e.g., Al3+). Here, we present first steps towards n-doped ZnO-based TCO materials via substitution in the anion lattice (O2− versus halogenides). A special approach is presented, using novel single-source precursors containing a potential excerpt of the target lattice 'HalZn·Zn3O3' preorganized on the molecular scale (Hal = I, Br, Cl). We report about the synthesis of the precursors, their transformation into halogene-containing ZnO materials, and finally structural, optical and electronic properties are investigated using a combination of techniques including FT-Raman, low-T photoluminescence, impedance and THz spectroscopies.

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Lu, Hui, Jinna Zhang, Qiuping Zhang et Jianzhou Gui. « Novel Ba0.15Sr0.85M0.15Fe0.85O3-δ (M = Fe, Co, Al, Ti) perovskite oxides for oxygen enrichment : Structural, electrical, and oxygen sorption/desorption properties ». Materials Science and Engineering : B 262 (décembre 2020) : 114686. http://dx.doi.org/10.1016/j.mseb.2020.114686.

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Jafari, Azadeh, SAA Terohid, Alireza Kokabi et Amir Moradiani. « Electrical, structural, and photocatalytic properties of copper oxide nanowire ». Journal of Chemical Research 44, n^o 7-8 (5 février 2020) : 471–74. http://dx.doi.org/10.1177/1747519819899068.

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Using a direct oxidation method in a horizontal quartz tube, copper oxide nanowires are grown on a Cu substrate. In order to investigate the growth temperature effects on the structural, morphological, electrical, and photocatalytic properties of the copper oxide nanowires, X-ray diffraction, scanning electron microscopy, a KEITHLEY 2361 system, and a homemade photoreactor are used. The X-ray diffraction results show that both CuO and Cu2O phases are formed, and while increasing the growth temperature, the crystallinity is improved and the intensity of most of the diffraction peaks increases. The scanning electron microscopy images at different growth temperatures show that the number, density, and length of the copper oxide nanowires on pre-formed micro-scaled grains increase, when the growth temperature increases to 700°C and sharper nanowires with average diameters of 1–3 µm grow on the surface. Also I–V curves show that by raising the growth temperature, the conductivity of the samples increases. In addition, the photocatalytic activities are studied by photocatalytic degradation of Congo red dye, and based on these results, the sample grown at 700°C with the highest number and density of the nanowires showed the best photocatalytic performance and electrical conductivity. The results can be used to guide better understanding of the growth behavior of copper oxide nanowires and can be useful for the development of novel photocatalytic nanodevices.

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Adimule, Vinayak, Vinay S. Bhat, Basappa C. Yallur, Adarsha HJ Gowda, Paola De Padova, Gurumurthy Hegde et Arafat Toghan. « Facile synthesis of novel SrO _0.5:MnO _0.5 bimetallic oxide nanostructure as a high-performance electrode material for supercapacitors ». Nanomaterials and Nanotechnology 12 (janvier 2022) : 184798042110640. http://dx.doi.org/10.1177/18479804211064028.

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Perovskite bimetallic oxides as electrode material blends can be an appropriate method to enhance the supercapacitor properties. In the present research, SrO 0.5:MnO 0.5 nanostructures (NS) were synthesized by a facile co-precipitation method and calcinated at 750–800°C. Crystal structure of SrO 0.5:MnO 0.5 NS were characterized by X-ray diffraction, surface chemical composition and chemical bond analysis, and dispersion of SrO into MnO was confirmed by X-ray photoelectron spectral studies. Structural morphology was analyzed from scanning electron microscopy. Optical properties of SrO 0.5:MnO 0.5 NS were studied using UV-Visible spectrophotometer and SrO 0.5 and MnO 0.5 NS showed ∼75 nm grain, ∼ 64 nm grain boundary distance, with two maxima at 261 nm and 345 nm as intensity of absorption patterns, respectively. The synthesized SrO 0.5:MnO 0.5 NS exhibited high specific capacitance of 392.8 F/g at a current density of 0.1 A/g. Electrochemical impedance spectroscopy results indicated low resistance and very low time constant of 0.2 s ∼73% of the capacitance was retained after 1000 galvanostatic charge-discharge (GCD) cycles. These findings indicate that SrO 0.5:MnO 0.5 bimetallic oxide material could be a promising electrode material for electrochemical energy storage systems.

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Isobe, Masaaki, Mitsuyuki Shizuya et Eiji Takayama-Muromachi. « Structural and physical properties of a novel misfit-layered cobalt oxide (CaOH)1.14CoO2 ». Physica C : Superconductivity and its Applications 460-462 (septembre 2007) : 477–78. http://dx.doi.org/10.1016/j.physc.2007.03.041.

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Ozawa, Takashi, Isao Suzuki et Hirohiko Sato. « Structural, Magnetic and Electronic Transport Properties of Novel Hollandite-Type Molybdenum Oxide, Rb1.5Mo8O16 ». Journal of the Physical Society of Japan 75, n^o 1 (15 janvier 2006) : 014802. http://dx.doi.org/10.1143/jpsj.75.014802.

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Wang, Jinying, Shibin Deng, Zhongfan Liu et Zhirong Liu. « The rare two-dimensional materials with Dirac cones ». National Science Review 2, n^o 1 (31 janvier 2015) : 22–39. http://dx.doi.org/10.1093/nsr/nwu080.

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Abstract Inspired by the great development of graphene, more and more research has been conducted to seek new two-dimensional (2D) materials with Dirac cones. Although 2D Dirac materials possess many novel properties and physics, they are rare compared with the numerous 2D materials. To provide explanation for the rarity of 2D Dirac materials as well as clues in searching for new Dirac systems, here we review the recent theoretical aspects of various 2D Dirac materials, including graphene, silicene, germanene, graphynes, several boron and carbon sheets, transition-metal oxides (VO2)n/(TiO2)m and (CrO2)n/(TiO2)m, organic and organometallic crystals, so-MoS2, and artificial lattices (electron gases and ultracold atoms). Their structural and electronic properties are summarized. We also investigate how Dirac points emerge, move, and merge in these systems. The von Neumann–Wigner theorem is used to explain the scarcity of Dirac cones in 2D systems, which leads to rigorous requirements on the symmetry, parameters, Fermi level, and band overlap of materials to achieve Dirac cones. Connections between existence of Dirac cones and the structural features are also discussed.

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Khan, Asfandyar, Zsolt Valicsek et Ottó Horváth. « Comparing the Degradation Potential of Copper(II), Iron(II), Iron(III) Oxides, and Their Composite Nanoparticles in a Heterogeneous Photo-Fenton System ». Nanomaterials 11, n^o 1 (16 janvier 2021) : 225. http://dx.doi.org/10.3390/nano11010225.

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Heterogeneous photo-Fenton systems offer efficient solutions for the treatment of wastewaters in the textile industry. This study investigated the fabrication and structural characterization of novel peculiar-shaped CuIIO, FeIII2O3, and FeIIO nanoparticles (NPs) compared to the properties of the iron(II)-doped copper ferrite CuII0.4FeII0.6FeIII2O4. The photocatalytic efficiencies of these NPs and the composite of the simple oxides (CuIIO/FeIIO/FeIII2O3) regarding the degradation of methylene blue (MB) and rhodamine B (RhB) as model dyes were also determined. The catalysts were synthesized via simple co-precipitation and calcination technique. X-ray diffractometry (XRD), scanning electron microscopy (SEM), and diffuse reflectance spectroscopy (DRS) were utilized for structural characterization. The structure of CuIIO was bead-like connected into threads, FeIII2O3 was rod-like, while FeIIO pallet-like, with average crystallite sizes of 18.9, 36.9, and 37.1 nm, respectively. The highest degradation efficiency was achieved by CuIIO for RhB and by CuII0.4FeII0.6FeIII2O4 for MB. The CuIIO/FeIIO/FeIII2O3 composite proved to be the second-best catalyst in both cases, with excellent reusability. Hence, these NPs can be successfully applied as heterogeneous photo-Fenton catalysts for the removal of hazardous pollutants. Moreover, the simple metal oxides and the iron(II)-doped copper ferrite displayed a sufficient antibacterial activity against Gram-negative Vibrio fischeri.

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Habermeier, Hanns-Ulrich. « Complex Oxide Interfaces : A Path to Design New Materials ». MRS Proceedings 1454 (2012) : 137–48. http://dx.doi.org/10.1557/opl.2012.924.

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ABSTRACTHeterostructures composed of transition metal oxides with strong electron correlation offer a unique opportunity to design new artificial materials whose electrical, magnetic and optical properties can be manipulated by tailoring the occupation of the d-orbitals of the transition metal in the compound. This possibility is an implication of symmetry constraints at interfaces with the consequence of a reconstruction of the coupled charge-, spin-, and orbital states of the constituents and their interactions. Novel architectures can be constructed showing functions well beyond charge density manipulations determining the functionality of conventional semiconductor heterostructures. Success in this endeavor requires the mastering of technological prerequisites such as structurally as well as chemically controlled interface preparation down to atomic scales. Additionally, a fundamental understanding of the modifications of the electronic structure at the interface imposed by structural boundary conditions and consequently by the constituent’s orbital occupation is required. A path towards a new generation of electronic devices with multiple functionalities can thus be opened by exploiting the correlation driven interface phenomena. In this paper, the technological challenges and experimental realizations along this concept are described with an emphasis of growth techniques based on the pulsed laser deposition method. As a case study, results of investigations of YBa2Cu3O7/La2/3Ca1/3MnO3superlattices are compiled and the conclusions regarding the orbital manipulation at the interface are used to pave the way for orbital engineering of oxides with electronic structures similar to the cuprates in order to find novel ordered quantum states at the interfaces including magnetism and superconductivity.

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LU, HUI, YAN ZHANG, CHUNLING YIN et YUJUN ZHANG. « STRUCTURAL, SINTERING AND OXYGEN SORPTION PROPERTIES OF A NOVEL Fe/Nb CO-DOPED PEROVSKITE Ba(Co0.8Fe0.1Nb0.1)O3-δ OXIDE ». Functional Materials Letters 04, n^o 01 (mars 2011) : 37–40. http://dx.doi.org/10.1142/s1793604711001579.

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The novel Fe/Nb co-doped Ba(Co0.8Fe0.1Nb0.1)O3-δ oxide was synthesized by the solid-state reaction method. Structural, sintering and oxygen sorption properties of the Ba(Co0.8 Fe0.1Nb0.1)O3-δ oxide were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetry (TG). The results demonstrate that the structural stability of the Fe/Nb co-doped Ba(Co0.8Fe0.1Nb0.1)O3-δ oxide is improved significantly. The oxygen sorption property of the Fe/Nb co-doped Ba(Co0.8Fe0.1Nb0.1)O3-δ oxide was investigated in air between 300°C and 900°C, and an oxygen sorption capacity of 7.0 mL(STP) O2 /g oxide is obtained.

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Kubacka, A., M. L. Cerrada, C. Serrano, M. Fernández-García, M. Ferrer et M. Fernández-García. « Light-Driven Novel Properties of TiO2-Modified Polypropylene-Based Nanocomposite Films ». Journal of Nanoscience and Nanotechnology 8, n^o 6 (1 juin 2008) : 3241–46. http://dx.doi.org/10.1166/jnn.2008.18323.

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Nanocomposite films obtained by TiO2 incorporation into a polypropylene (PP) polymer matrix were prepared via a straightforward melting process. The structural characteristics of the nanocomposite materials were examined by a multitechnique approach showing the outstanding morphological uniformity of the films. TiO2 incorporation into the polymer matrix renders self-sterilized and self-degradable materials which showed an impressive performance against gram-positive, gram-negative, coccus and yeast micro-organisms. Optimization of the novel properties of TiO2-PP nanocomposite films is reached with a 2 wt% of oxide content loading. The physico-chemical bases of this optimum are discussed.

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da Silva, Bianca A., Michael Nazarkovsky, Helmut Isaac Padilla-Chavarría, Edith Alejandra C. Mendivelso, Heber L. de Mello, Cauê de S. C. Nogueira, Rafael dos S. Carvalho et al. « Novel Scintillating Nanoparticles for Potential Application in Photodynamic Cancer Therapy ». Pharmaceutics 14, n^o 11 (22 octobre 2022) : 2258. http://dx.doi.org/10.3390/pharmaceutics14112258.

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The development of X-ray-absorbing scintillating nanoparticles is of high interest for solving the short penetration depth problem of visible and infrared light in photodynamic therapy (PDT). Thus, these nanoparticles are considered a promising treatment for several types of cancer. Herein, gadolinium oxide nanoparticles doped with europium ions (Gd2O3:Eu3+) were obtained by using polyvinyl alcohol as a capping agent. Hybrid silica nanoparticles decorated with europium-doped gadolinium oxide (SiO2-Gd2O3:Eu3+) were also prepared through the impregnation method. The synthesized nanoparticles were structurally characterized and tested to analyze their biocompatibility. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy confirmed the high crystallinity and purity of the Gd2O3:Eu3+ particles and the homogeneous distribution of nanostructured rare earth oxides throughout the fumed silica matrix for SiO2-Gd2O3:Eu3+. Both nanoparticles displayed stable negative ζ-potentials. The photoluminescence properties of the materials were obtained using a Xe lamp as an excitation source, and they exhibited characteristic Eu3+ bands, including at 610 nm, which is the most intense transition band of this ion. Cytotoxicity studies on mouse glioblastoma GL261 cells indicated that these materials appear to be nontoxic from 10 to 500 μg·mL−1 and show a small reduction in viability in non-tumor cell lines. All these findings demonstrate their possible use as alternative materials in PDT.

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Jiao, Yang, Shenghan Zhang et Yu Tan. « Thermodynamic Analysis and Crystallographic Properties of MFe2O4, MCr2O4 and MAl2O4 (M = Fe, Ni, Zn) Formed on Structural Materials in Pressurized Water Reactor Primary Circuit under Zinc and Zinc-aluminum Water Chemistry ». Entropy 24, n^o 2 (6 février 2022) : 245. http://dx.doi.org/10.3390/e24020245.

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Zinc injection technology (zinc water chemistry, ZWC) was widely applied in pressurized water reactor (PWR) primary circuits to reduce radiation buildup and improve corrosion resistance of structural materials. The simultaneous injection of zinc-aluminium (ZAWC) is a novel implement created to replace part of Zn2+ by Al3+. It was reported ZAWC can improve further corrosion resistance of carbon steels and stainless steels. However, ZAWC sometimes showed even negative effects on Nickel-alloys. In this study, mechanism of formation of oxide film on metals was investigated. The reactions of Fe2+ Ni2+ in oxide films replaced by Zn2+, or Fe3+ replaced by Al3+ in ZAWC were analysed. The thermodynamic data and solubility of mixed oxides (ZnFe2O4, ZnCr2O4, and ZnAl2O4), the products of replace reactions, were calculated. According to the Gibbs free energy difference between products and reactants, ΔGθ(T) values of the formation reaction of ZnFe2O4, ZnCr2O4, and ZnAl2O4 are extremely negative. Solubility of ZnAl2O4 is the lowest among mixed oxide products, which implies the oxide film composites of ZnAl2O4 may show a lower corrosion rate. In addition, the preferential formation of NiAl2O4 on Ni-based-alloy, under ZAWC, was discussed based on crystallographic properties of spinel, which was considered as the cause of negative effects of ZAWC on corrosion resistance of Nickel-alloys. This research provides an analytical basis for the study of thermodynamic stability of oxide films under different chemical chemistry and a theoretical basis for improving corrosion resistance of different metals and optimizing the chemical conditions of PWR primary circuit.

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Jayachandran, Varuna, Vishnu Shankar Dhandapani, Elango Muniappan, Dongkyou Park, Byungki Kim, A. P. Arun et P. R. Ayyappan. « Assessment of the Synergetic Performance of Nanostructured CeO2-SnO2/Al2O3 Mixed Oxides on Automobile Exhaust Control ». Materials 15, n^o 23 (28 novembre 2022) : 8460. http://dx.doi.org/10.3390/ma15238460.

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In order to control diesel exhaust emission, CeO2-SnO2/Al2O3 (CTA) mixed oxides were prepared and coated on perforated stainless steel (SS) filter plates, and the catalytic activities were analyzed in this work. The CeO2-SnO2 (different compositions of Ce/Sn—2:8; 1:1; 8:2) composites and Al2O3 were prepared separately via a co-precipitation approach, and CeO2-SnO2/Al2O3 (CTA) mixed oxides were attained by mechanical mixing of 75 wt% CeO2-SnO2 composites with 25 wt% Al2O3. X-ray diffraction (XRD) and Raman spectroscopy were performed for all three CeO2-SnO2/Al2O3 (CTA) mixed oxides; the CeO2-SnO2/Al2O3 (Ce/Sn-1:1) sample confirmed the presence of cubic and tetragonal mixed faces, which enhances the redox nature (catalytic activities). Various characterizations such as high-resolution transmission electron microscopy (HRTEM), Brunauer–Emmett–Teller (BET) analysis, X-ray photoelectron spectroscopy (XPS), and a scanning electron microscope (SEM) were employed on CeO2-SnO2/Al2O3 (Ce/Sn-1:1) sample to investigate the structural, textural, compositional, and morphological properties. The CeO2-SnO2/Al2O3 (Ce/Sn-1:1) sample was coated on a perforated stainless steel (SS) filter plate via a simple, cost-effective, and novel method, and an exhaust emission test for various compression ratios (CR), injection pressure (IP), and load (L) was completed using an AVL Digas analyzer. The CeO2-SnO2/Al2O3 (Ce/Sn-1:1) sample, with a size of 10.22 nm and a high surface area of about 73 m2 g−1, exhibit appreciable catalytic properties.

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Reschetilowski, Wladimir, Matthias Hauser, Felix Alscher, Mandy Klauck et Grit Kalies. « Studies on the Binary MgO/SiO2 Mixed Oxide Catalysts for the Conversion of Ethanol to 1,3-Butadiene ». Catalysts 10, n^o 8 (1 août 2020) : 854. http://dx.doi.org/10.3390/catal10080854.

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The demand for 1,3-butadiene, one of the most important raw materials in the rubber industry, is constantly increasing. The Lebedev process is a classical method of producing 1,3-butadiene from ethanol, which is to be optimized with regard to the mixed oxide catalysts used. In this work, the binary MgO/SiO2 solid system was tested with regard to its optimum chemical composition for the catalytic conversion of ethanol to 1,3-butadiene. Furthermore, novel mesoporous mixed oxides were prepared to investigate their textural, structural, and surface chemical properties as well as the catalytic activity. Nitrogen physisorption, scanning electron microscopy (SEM), and temperature-programmed ammonia desorption (NH3-TPD) measurements were carried out and evaluated. It was shown that the optimum yield of 1,3-butadiene is achieved by using MgO/SiO2 mixed oxide catalysts with 85–95 mol% MgO and not, as suggested by Lebedev, with 75 mol% MgO. The NH3-TPD measurements revealed that the maximum acid-site density is achieved with an equimolar up to magnesium-rich composition. During the synthesis of binary MgO/SiO2 solid systems based on mesoporous MgO, a thermally stable and ordered structure was formed in the autoclave, depending on the carbonate used and on the duration of the treatment.

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Lu, Hui, Jong Pyo Kim, Sou Hwan Son et Jung Hoon Park. « Novel SrCo1−2x(Fe,Nb)xO3−δ (x=0.05, 0.10) oxides targeting CO2 capture and O2 enrichment : Structural stability and oxygen sorption properties ». Materials Letters 65, n^o 19-20 (octobre 2011) : 2858–60. http://dx.doi.org/10.1016/j.matlet.2011.06.062.

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Zhong, Haihong, Carlos Campos-Roldán, Yuan Zhao, Shuwei Zhang, Yongjun Feng et Nicolas Alonso-Vante. « Recent Advances of Cobalt-Based Electrocatalysts for Oxygen Electrode Reactions and Hydrogen Evolution Reaction ». Catalysts 8, n^o 11 (19 novembre 2018) : 559. http://dx.doi.org/10.3390/catal8110559.

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This review summarizes recent progress in the development of cobalt-based catalytic centers as the most potentially useful alternatives to noble metal-based electrocatalysts (Pt-, Ir-, and Ru-based) towards the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) in acid and alkaline media. A series of cobalt-based high-performance electrocatalysts have been designed and synthesized including cobalt oxides/chalcogenides, Co–Nx/C, Co-layered double hydroxides (LDH), and Co–metal-organic frameworks (MOFs). The strategies of controllable synthesis, the structural properties, ligand effect, defects, oxygen vacancies, and support materials are thoroughly discussed as a function of the electrocatalytic performance of cobalt-based electrocatalysts. Finally, prospects for the design of novel, efficient cobalt-based materials, for large-scale application and opportunities, are encouraged.

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Łaszcz, Adam, Andrzej Czerwiński, Jacek Ratajczak, Andrzej Taube, Sylwia Gierałtowska, Ania Piotrowska et Jerzy Kątcki. « Study of Oxides Formed in HfO₂/Si Structure for High-k Dielectric Applications ». Solid State Phenomena 186 (mars 2012) : 78–81. http://dx.doi.org/10.4028/www.scientific.net/ssp.186.78.

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Transmission electron microscopy (TEM) techniques were used for characterization of annealing (400, 600 and 800 °C) influence on the structural properties of the HfO2 film (45 nm thick) deposited on Si substrate. Such structures are considered as high-k dielectric materials for application in novel semiconductor devices. The studies showed that independently of the annealing temperature a very thin and flat amorphous layer is formed between HfO2 layer and Si substrate. This result was also found in the non-annealed sample. EDXS examination confirmed that the stoichiometry for the hafnium oxide layer in each sample corresponds to 1:2 for Hf:O (i.e. to HfO2). TEM images revealed differences in the microstructure of HfO2 layers in annealed samples, however the layers have similar thickness and interface roughness in all studied samples.

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Kaczmarek, Wieslaw A. « Structural and magnetic properties of cobalt-doped iron oxide particles prepared by novel mechanochemical method ». Journal of Magnetism and Magnetic Materials 157-158 (mai 1996) : 264–65. http://dx.doi.org/10.1016/0304-8853(95)01095-5.

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Vanam, Sai Pranav, et Prabeer Barpanda. « (Invited, Digital Presentation) Design of New Cathodes for Sodium-Ion Batteries Harnessing Anionic Redox Activity : Two Case Studies ». ECS Meeting Abstracts MA2022-02, n^o 4 (9 octobre 2022) : 457. http://dx.doi.org/10.1149/ma2022-024457mtgabs.

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Sodium-ion batteries (SIBs) are widely pursued as pragmatic alternative to the Li-ion battery technology having close operational similarity along with natural resource abundance. In this sector, apart from classical cationic redox-based cathodes, various new cathodes have been unveiled based on anionic (oxygen) redox activity. In this work, we will showcase two such case studies of novel cathode composition for SIBs exploiting anionic redox activity. (1) P2-type manganese-rich layered oxides offers high capacity along with fast rate kinetics. To improve their electrochemical properties, reduce voltage decay upon cycling and to mitigate irreversible phase transitions, cation doping or hybrid composite integrations can be explored. We have tested a unique Mn-rich layer-spinel composite, Na0.7(Li1/18Mn11/18Ni3/18Fe2/181 /18)O2–xNa2MoO4, leading to a synergistic effect of layered P2 and spinel phases. This layer/spinel biphasic composite was stabilised through Mo doping and its electrochemical activity was studied at different voltage windows. Upon cycling between 1.5–4.5 V, this Mo-based composite exhibited a high specific capacity of 183 mAh.g-1 involving both cationic and anionic (O2-/O2 n-) redox activity. The structural evolution during (dis)charge was studied by ex-situ X-ray diffraction and cyclic voltammetry. It is observed that mitigating P2-P2´´ phase transition at higher voltage is crucial to improve the electrochemical performance, cycling stability and reduce the voltage hysteresis. The structural and electrochemical properties of this new composite cathode will be described (Fig. a) (manuscript submitted). (2) The second part will dwell on anionic redox activity of Na-based mixed-metal oxide cathode [Na0.7Mn0.6Ni0.3Co0.1O2]. Combining cationic and anionic redox activity, it exhibited a reversible capacity of 120 mAh/g with anionic redox activity centered around 4.3 V (Fig. b). The underlying redox mechanism has been investigated using in-situ XRD and Raman spectroscopy showing peroxo bond formation (Fig. c). The structural and electrochemical properties of this new cathode composition will be explained (manuscript submitted). Figure 1

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Waychunas, G. A. « Natural nanoparticle structure, properties and reactivity from X-ray studies ». Powder Diffraction 24, n^o 2 (juin 2009) : 89–93. http://dx.doi.org/10.1154/1.3132590.

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Synthetic analogs of naturally occurring nanoparticles have been studied by a range of X-ray techniques to determine their structure and chemistry, and relate these to their novel chemical properties and physical behavior. ZnS nanoparticles, formed in large concentrations naturally bymicrobial action, have an interesting core-shell structure with a highly distorted and strained outer layer. The strain propagates through the particles and produces unusual stiffness but can be relieved by changing the nature of the surface ligand binding. Weaker bound ligands allow high surface distortion, but strongly bound ligands relax this structure and reduce the overall strain. Only small amounts of ligand exchange causes transformations from the strained to the relaxed state. Most remarkably, minor point contacts between strained nanoparticles also relax the strain. Fe oxyhydroxide nanoparticles appear to go through structural transformations dependent on their size and formation conditions, and display a crystallographically oriented form of aggregation at the nanoscale that alters growth kinetics. At least one Fe oxyhydroxide mineral may only be stable on the nanoscale, and nonstoichiometry observed on the hematite surface suggests that for this phase and possibly other natural metal oxides, chemistry may be size dependent. Numerous questions exist on nanominerals formed in acid mine drainage sites and by reactions at interfaces.

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Alhalili, Zahrah. « Metal Oxides Nanoparticles : General Structural Description, Chemical, Physical, and Biological Synthesis Methods, Role in Pesticides and Heavy Metal Removal through Wastewater Treatment ». Molecules 28, n^o 7 (30 mars 2023) : 3086. http://dx.doi.org/10.3390/molecules28073086.

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Nanotechnology (NT) is now firmly established in both the private home and commercial markets. Due to its unique properties, NT has been fully applied within multiple sectors like pharmacy and medicine, as well as industries like chemical, electrical, food manufacturing, and military, besides other economic sectors. With the growing demand for environmental resources from an ever-growing world population, NT application is a very advanced new area in the environmental sector and offers several advantages. A novel template synthesis approach is being used for the promising metal oxide nanostructures preparation. Synthesis of template-assisted nanomaterials promotes a greener and more promising protocol compared to traditional synthesis methods such as sol-gel and hydrothermal synthesis, and endows products with desirable properties and applications. It provides a comprehensive general view of current developments in the areas of drinking water treatment, wastewater treatment, agriculture, and remediation. In the field of wastewater treatment, we focus on the adsorption of heavy metals and persistent substances and the improved photocatalytic decomposition of the most common wastewater pollutants. The drinking water treatment section covers enhanced pathogen disinfection and heavy metal removal, point-of-use treatment, and organic removal applications, including the latest advances in pesticide removal.

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Artem’ev, Alexander V., Evgeniya P. Doronina, Marianna I. Rakhmanova, Anastasiya O. Sutyrina, Irina Yu Bagryanskaya, Peter M. Tolstoy, Artem L. Gushchin, Anton S. Mazur, Nina K. Gusarova et Boris A. Trofimov. « Luminescent CuI thiocyanate complexes based on tris(2-pyridyl)phosphine and its oxide : from mono-, di- and trinuclear species to coordination polymers ». New Journal of Chemistry 40, n^o 12 (2016) : 10028–40. http://dx.doi.org/10.1039/c6nj02087a.

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Pappacena, Alfonsina, Marta Boaro, Olga Šolcová et Alessandro Trovarelli. « Ceria Based Materials with Enhanced OSC Properties for H₂ Production by Water Splitting Reaction ». Advances in Science and Technology 93 (octobre 2014) : 76–81. http://dx.doi.org/10.4028/www.scientific.net/ast.93.76.

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A novel surfactant-assisted synthesis method was developed in our laboratory to enhance the oxygen storage capacity (OSC) and the thermo stability of a TWC catalyst based on zirconia and rare earth oxides. The same procedure was used to prepare ceria-zirconia compositions with different amount of ceria, either undoped or doped with La and Nd. The potential use of these materials in a two steps solar thermochemical water splitting cycle for the production of H2 was investigated. For this proposal the O2 release of the materials was measured through thermogravimetric analysis in N2 at 1573K. Then all prepared compositions were subjected to an aging treatment at temperature above 1573K in air or in N2 flow and their activity in producing H2 via water splitting at 1073K was evaluated with respect their structural evolution. The results obtained highlight that the reactivity depends on the temperature and atmosphere of the treatments and on the composition. The best result was obtained for the ceria rich composition treated at 1573K in N2 and for the corresponding doped composition treated in air.

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Mukundan, Vineetha, Karsten Beckmann, Kandabara Tapily, Steven Consiglio, Robert Clark, Gert Leusink, Nathaniel Cady et Alain C. Diebold. « Structural Correlation of Ferroelectric Behavior in Mixed Hafnia-Zirconia High-k Dielectrics for FeRAM and NCFET Applications ». MRS Advances 4, n^o 09 (2019) : 545–51. http://dx.doi.org/10.1557/adv.2019.148.

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ABSTRACTThe recent discovery of ferroelectric behavior in doped hafnia-based dielectrics, attributed to a non-centrosymmetric orthorhombic phase, has potential for use in attractive applications such as negative differential capacitance field-effect-transistors (NCFET) and ferroelectric random access memory devices (FeRAM). Alloying with similar oxides like ZrO2, doping with specific elements such as Si, novel processing methods, encapsulation and annealing schemes are also some of the techniques that are being explored to target structural modifications and stabilization of the non-centrosymmetric phase. In this study, we utilized synchrotron-based x-ray diffraction in the grazing incidence in plane geometry (GIIXRD) to determine the crystalline phases in hafnia-zirconia (HZO) compositional alloys deposited by atomic layer deposition (ALD). Here we compare and contrast the structural phases and ferroelectric properties of mechanically confined HZO films in metal-insulator-metal (MIM) and metal-insulator-semiconductor (MIS) structures. Both MIM and MIS structures reveals a host of reflections due to non-monoclinic phases in the d-spacing region between 1.75Å to 4Å. The non-monoclinic phases are believed to consist of tetragonal and orthorhombic phases. Compared to the MIS structures a suppression of the monoclinic phase in MIM structures with 50% zirconia or less was observed. The correlation of the electrical properties with the structural analysis obtained by GIIXRD highlights the importance of understanding the effects of the underlying substrate (metal vs. Si) for different target applications.

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Chithambararaj, A., et A. Chandra Bose. « Microwave Assisted Ultra Fast Synthesis of 1-D Molybdenum Oxide Nanocrystals : Structural and Electrical Studies ». Advanced Materials Research 488-489 (mars 2012) : 940–44. http://dx.doi.org/10.4028/www.scientific.net/amr.488-489.940.

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Molybdenum oxide (MoO3) is a well known transition metal oxide with multi phase properties that permit novel applications in sensors and batter systems. In this paper, we report a new approach to synthesize meta-stable structured molybdenum oxide (MoO3) by microwave assisted solution precipitation method using a domestic microwave oven. The reaction is carried out in a short period of 5 min. The XRD results confirms that the powder exhibits single phase hexagonal MoO3 with lattice parameter a= 10.53 Å and c = 14.907 Å. SEM images show, the particles are one dimensional (1-D) structure with hexagonal cross section and EDX spectrum confirm that the particles comprise of only molybdenum and oxygen. Further, the thermal and electrical properties are investigated by thermo gravimetric and impedance analysis and the results are discussed.

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Abdul-ameer, Zehraa Najim. « Novel Co-Precipitation method for synthesis of Nanostructured Nickel Oxide in accordance to PH : Structural and Optical Properties as an Active optical filter ». Ibn AL- Haitham Journal For Pure and Applied Science 32, n^o 1 (10 février 2019) : 1. http://dx.doi.org/10.30526/32.1.1974.

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Low cost Co-Precipitation method was used for Preparation of novel nickel oxide (NiO) nano particle thin films with Simple, with two different PH values 6, 12 and its effect on structural and optical properties as an active optical filter. Experimental results of structural properties X-ray diffraction (XRD) showed that both Nickel oxide nanoparticles with (PH=6 and 12) have polycrystalline structure smaller average particle size about 8.5 nm for PH=6 in comparison with PH=12. Morphological studies using Scanning electron microscopy (SEM) and atomic force microscope (AFM) show uniform nano rod distribution for PH=6 with smaller average diameter, average roughness as compared with NiO with PH=12 that showed larger diameter ,grain size , spherical shape with scope of excellent sensing applications due to high roughness .Optical properties results Show blue shift for PH=6 as compared with PH=12m leading to potential of optoelectronic applications and as active optical

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