Articles de revues : « Metal supported nanoparticle »

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Petek, Urša, Francisco Ruiz-Zepeda, Marjan Bele et Miran Gaberšček. « Nanoparticles and Single Atoms in Commercial Carbon-Supported Platinum-Group Metal Catalysts ». Catalysts 9, n^o 2 (1 février 2019) : 134. http://dx.doi.org/10.3390/catal9020134.

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Nanoparticles of platinum-group metals (PGM) on carbon supports are widely used as catalysts for a number of chemical and electrochemical conversions on laboratory and industrial scale. The newly emerging field of single-atom catalysis focuses on the ultimate level of metal dispersion, i.e. atomically dispersed metal species anchored on the substrate surface. However, the presence of single atoms in traditional nanoparticle-based catalysts remains largely overlooked. In this work, we use aberration-corrected scanning transmission electron microscope to investigate four commercially available nanoparticle-based PGM/C catalysts (PGM = Ru, Rh, Pd, Pt). Annular dark-field (ADF) images at high magnifications reveal that in addition to nanoparticles, single atoms are also present on the surface of carbon substrates. Scanning electron microscopy, X-ray diffraction and size distribution analysis show that the materials vary in nanoparticle size and type of carbon support. These observations raise questions about the possible ubiquitous presence of single atoms in conventional nanoparticle PGM/C catalysts and the role they may play in their synthesis, activity, and stability. We critically discuss the observations with regard to the quickly developing field of single atom catalysis.

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Yim, Chi Ming, Chi L. Pang, Diego R. Hermoso, Coinneach M. Dover, Christopher A. Muryn, Francesco Maccherozzi, Sarnjeet S. Dhesi, Rubén Pérez et Geoff Thornton. « Influence of support morphology on the bonding of molecules to nanoparticles ». Proceedings of the National Academy of Sciences 112, n^o 26 (15 juin 2015) : 7903–8. http://dx.doi.org/10.1073/pnas.1506939112.

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Supported metal nanoparticles form the basis of heterogeneous catalysts. Above a certain nanoparticle size, it is generally assumed that adsorbates bond in an identical fashion as on a semiinfinite crystal. This assumption has allowed the database on metal single crystals accumulated over the past 40 years to be used to model heterogeneous catalysts. Using a surface science approach to CO adsorption on supported Pd nanoparticles, we show that this assumption may be flawed. Near-edge X-ray absorption fine structure measurements, isolated to one nanoparticle, show that CO bonds upright on the nanoparticle top facets as expected from single-crystal data. However, the CO lateral registry differs from the single crystal. Our calculations indicate that this is caused by the strain on the nanoparticle, induced by carpet growth across the substrate step edges. This strain also weakens the CO–metal bond, which will reduce the energy barrier for catalytic reactions, including CO oxidation.

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Köhler, Johann, et Andrea Knauer. « The Mixed-Electrode Concept for Understanding Growth and Aggregation Behavior of Metal Nanoparticles in Colloidal Solution ». Applied Sciences 8, n^o 8 (10 août 2018) : 1343. http://dx.doi.org/10.3390/app8081343.

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The growth and aggregation behavior of metal nanoparticles can be modulated by surfactants and different other additives. Here the concept of how open-circuit mixed electrodes helps to understand the electrical aspects of nanoparticle growth and the consequences for the particle geometries is discussed. A key issue is the self-polarization effect of non-spherical metal nanoparticles, which causes a local decoupling of anodic and partial processes and asymmetry in the local rates of metal deposition. These asymmetries can contribute to deciding to the growth of particles with high aspect ratios. The interpretation of electrochemical reasons for particle growth and behavior is supported by experimental results of nanoparticle syntheses supported by microfluidics which can supply high yields of non-spherical nanoparticles and colloidal product solutions of high homogeneity.

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Okazaki, Tomohisa, Satoshi Seino, Junichiro Kugai, Yuji Ohkubo, Takashi Nakagawa et Takao A. Yamamoto. « Effect of pH on Nanoparticle Structure in Radiochemical Synthesis of PtCu Alloy Supported on γ-Fe2O3 and Carbon ». MRS Advances 1, n^o 6 (2016) : 427–32. http://dx.doi.org/10.1557/adv.2016.30.

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ABSTRACTPtCu nanoparticles were synthesized with different pH and support conditions using radiochemical process. The nanoparticle structures were characterized by transmission electron microscopy, inductively coupled plasma atomic emission spectrometry, X-ray absorption spectroscopy, and X-ray diffraction techniques. The nanoparticle structure was relevant to the pH of the precursor solutions. The lattice parameter of PtCu alloy increased in high pH samples, which indicates the critical effect of metal ion adsorption in precursor solution on nanoparticle structure.

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Sasaki, Teruyoshi, Yusuke Horino, Tadashi Ohtake, Kazufumi Ogawa et Yoshifumi Suzaki. « A Highly Efficient Monolayer Pt Nanoparticle Catalyst Prepared on a Glass Fiber Surface ». Catalysts 10, n^o 5 (25 avril 2020) : 472. http://dx.doi.org/10.3390/catal10050472.

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Over the past few years, various nanoparticle-supported precious metal-based catalysts have been investigated to reduce the emission of harmful substances from automobiles. Generally, precious metal nanoparticle-based exhaust gas catalysts are prepared using the impregnation method. However, these catalysts suffer from the low catalytic activity of the precious metal nanoparticles involved. Therefore, in this study, we developed a novel method for preparing highly efficient glass fiber-supported Pt nanoparticle catalysts. We uniformly deposited a single layer of platinum particles on the support surface using a chemically adsorbed monomolecular film. The octane combustion performance of the resulting catalyst was compared with that of a commercial catalyst. The precious metal loading ratio of the proposed catalyst was approximately seven times that of the commercial catalyst. Approximately one-twelfth of the mass of the proposed catalyst exhibited a performance comparable to that of the commercial catalyst. Thus, the synthesis method used herein can be used to reduce the weight, size, and manufacturing cost of exhaust gas purification devices used in cars.

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Serp, Philippe. « Cooperativity in supported metal single atom catalysis ». Nanoscale 13, n^o 12 (2021) : 5985–6004. http://dx.doi.org/10.1039/d1nr00465d.

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Cooperativity in single atom catalysis greatly exceeds the (important) metal–support interaction, and other types of synergies (with a nanoparticle – NP, a second SA – SA₂, or a ligand/heteroatom – X) are described in this mini-review.

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Kim, Gil Pyo, Seung Bum Yoon, Young Soo Jung, Jae Hoon Ahn, Sung Hyeon Baeck, Alan Kleiman-Schwarsctein et Eric W. Mc Farland. « Fabrication of Nanoparticles Supported on Metal Oxides by PS-PVP Block Copolymer Encapsulation Method ». Solid State Phenomena 119 (janvier 2007) : 17–20. http://dx.doi.org/10.4028/www.scientific.net/ssp.119.17.

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Nanoparticles (Au, Pt, Ru) supported on metal oxides (TiO2, Heteropoly Acid) were prepared by PS-PVP block copolymer encapsulation method. It was confirmed by XPS analysis that the oxidation state of metal is 0 after calcination, which indicates the complete removal of polymer. Synthesized catalysts were characterized by TEM, SEM-EDS, and UV-VIS spectroscopy and it was observed that synthesis and calcination conditions, and the interaction between nanoparticle and metal oxide affected significantly the particle size of metal on the surface of metal oxide. When two different metal precursors were diffused into the core of inversed micelles, nano alloy could be synthesized and the composition of nano alloy was controlled by varying the ratio between the two metal precursors.

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Motshekga, Sarah C., Sreejarani K. Pillai, Suprakas Sinha Ray, Kalala Jalama et Rui W. M. Krause. « Recent Trends in the Microwave-Assisted Synthesis of Metal Oxide Nanoparticles Supported on Carbon Nanotubes and Their Applications ». Journal of Nanomaterials 2012 (2012) : 1–15. http://dx.doi.org/10.1155/2012/691503.

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The study of coating carbon nanotubes with metal/oxides nanoparticles is now becoming a promising and challenging area of research. To optimize the use of carbon nanotubes in various applications, it is necessary to attach functional groups or other nanostructures to their surface. The combination of the distinctive properties of carbon nanotubes and metal/oxides is expected to be applied in field emission displays, nanoelectronic devices, novel catalysts, and polymer or ceramic reinforcement. The synthesis of these composites is still largely based on conventional techniques, such as wet impregnation followed by chemical reduction of the metal nanoparticle precursors. These techniques based on thermal heating can be time consuming and often lack control of particle size and morphology. Hence, there is interest in microwave technology recently, where using microwaves represents an alternative way of power input into chemical reactions through dielectric heating. This paper covers the synthesis and applications of carbon-nanotube-coated metal/oxides nanoparticles prepared by a microwave-assisted method. The reviewed studies show that the microwave-assisted synthesis of the composites allows processes to be completed within a shorter reaction time with uniform and well-dispersed nanoparticle formation.

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Matus, E. V., L. M. Khitsova, O. S. Efimova, S. A. Yashnik, N. V. Shikina et Z. R. Ismagilov. « Preparation of Carbon Nanotubes with Supported Metal Oxide Nanoparticles : Effect of Metal Precursor on Thermal Decomposition Behavior of the Materials ». Eurasian Chemico-Technological Journal 21, n^o 4 (18 décembre 2019) : 303. http://dx.doi.org/10.18321/ectj887.

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To develop new catalysts based on carbon nanomaterials with supported metal oxide nanoparticles for oxidative transformations of sulfur compounds, a series of metal oxide nanoparticle-decorated carbon nanotubes (MOx/CNTs) were prepared by incipient wetness impregnation at a variation of the active metal type (M = Ce, Mo, Cu). The thermal decomposition of bulk and CNT supported metal precursors used in the preparation of MOx/CNTs was analyzed under inert atmosphere employing several thermoanalytical techniques (thermogravimetry, differential thermogravimetry and differential scanning calorimetry) coupled with mass spectrometry. The thermolysis parameters of the bulk and supported metal precursors were compared and the effect of CNT support on the decomposition pattern of compounds was elucidated. It was established that the decomposition of metal precursors supported on CNTs was started and completed at temperatures of 15‒25 and 25‒70 °C lower, respectively, compared with the bulk active metal precursor. The enhancement of CNT support stability against thermal degradation is observed in the following row of metal cations: Ce < Cu < Мо < pristine and metal anions of precursor: nitrate < chloride < sulfate. The optimal mode of thermal treatment of catalyst and appropriate active metal precursors were selected for advanced synthesis of nanosized MOx/CNT catalyst.

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Rout, Lipeeka, Prashanth Rengasamy, Basanti Ekka, Aniket Kumar et Priyabrat Dash. « Supported Bimetallic AgSn Nanoparticle as an Efficient Photocatalyst for Degradation of Methylene Blue Dye ». Nano 10, n^o 04 (juin 2015) : 1550059. http://dx.doi.org/10.1142/s1793292015500599.

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We report the synthesis of TiO 2-supported monometallic Ag , Sn and bimetallic AgSn nanoparticle catalysts prepared using sol–gel method via a rational nanoparticle encapsulation route. The samples were thoroughly characterized by ultraviolet-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) with image mapping and Brunauer–Emmett–Teller (BET) surface area analyzer. The supported bimetallic AgSn catalyst had the anatase structure, surface area of 50 m2/g and 2.6 ± 0.6 nm particle size. The efficiency of the catalysts was evaluated on photodegradation of methylene blue (MB) dye under visible light. The photocatalytic activity of MB was significantly enhanced in the presence of bimetallic AgSn nanoparticles (NPs) as compared to individual metal nanoparticles. Reusability study of the photocatalyst showed that the catalyst can be reused upto 5 runs with minimal loss in activity. Kinetic study revealed that the degradation reaction follows a pseudo first-order pathway.

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Zheng, Nanfeng, et Galen D. Stucky. « A General Synthetic Strategy for Oxide-Supported Metal Nanoparticle Catalysts ». Journal of the American Chemical Society 128, n^o 44 (novembre 2006) : 14278–80. http://dx.doi.org/10.1021/ja0659929.

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Kong, Tung Shing Adam, Kai Man Kerry Yu et Shik Chi Tsang. « Silica Coated Noble Metal Nanoparticle Hydrosols as Supported Catalyst Precursors ». Journal of Nanoscience and Nanotechnology 6, n^o 4 (1 avril 2006) : 1167–72. http://dx.doi.org/10.1166/jnn.2006.165.

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Gliech, Manuel, Malte Klingenhof, Mikaela Görlin et Peter Strasser. « Supported metal oxide nanoparticle electrocatalysts : How immobilization affects catalytic performance ». Applied Catalysis A : General 568 (novembre 2018) : 11–15. http://dx.doi.org/10.1016/j.apcata.2018.09.023.

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Costa, Natalia J. S., et Liane M. Rossi. « Synthesis of supported metal nanoparticle catalysts using ligand assisted methods ». Nanoscale 4, n^o 19 (2012) : 5826. http://dx.doi.org/10.1039/c2nr31165h.

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Gong, Qing, Qi Zhang, Hong Zhang, David A. Cullen, Sungho Jeon, Haoran Yu, Yang Ren et al. « Amino Functionalization Approach to Synthesis of Carbon Supported Intermetallic Platinum-Based Alloy Catalysts for Fuel Cell Application ». ECS Meeting Abstracts MA2022-02, n^o 42 (9 octobre 2022) : 1548. http://dx.doi.org/10.1149/ma2022-02421548mtgabs.

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Platinum (Pt) is a critical element in making electrocatalysts for oxygen reduction reaction (ORR) occurring at the cathode of polymer electrolyte membrane fuel cells (PEMFCs). To address the Pt abundance issue and to enhance Pt catalysis, Pt is often alloyed with another transition metal M (i.e. M = Fe, Co, and Ni). Ordered intermetallic PtM alloys are considered as one of the most promising candidates to achieve both high activity and stability in practical fuel cell applications. The transition metals in ordered intermetallic PtM alloys occupy specific sites, and are stabilized by both metallic and ionic bonding. Ordered intermetallic structures are formed via high temperature (>600 °C) annealing of disordered PtM alloys, as the atomic ordering is a thermodynamically driven process. However, the high temperature annealing inevitably leads to the migration and agglomeration of the nanoparticles forming randomly alloyed particles with poor dispersion and broad size distributions, due to weak adhesions to the carbon support under typical processing conditions. To prevent this coalescence during annealing, protective coating of the nanoparticles with inorganic shells or physical barriers has been suggested. However, these studies were limited to the synthesis of intermetallic nanoparticles on carbon supports at low metal loadings, or require an additional step of removing the coating layer from the surface of the nanoparticles to expose the active sites. Thus, it is essential to develop a general approach that can produce highly dispersed, structurally ordered nanoparticles while achieving controls over the size and size distribution. We propose to use the functionalized carbon supports to control PtM alloy nanoparticle size and prevent nanoparticles from aggregating during the high temperature annealing through improving the metal-support interactions. A strong electrostatic attraction between the negative charge from Pt precursor (PtCl6 2 -) and positive charge from the amino groups (C-NH2+) on the surface of the functionalized carbon will be established during the wet impregnation synthesis. Such bonds will help to make the PtM nanoparticle size smaller and more uniformly distributed over the surface of support. The ordered intermetallic 30 wt.% PtCo/KB-NH2 catalyst demonstrated an average size of 2.7 nm and uniform size distribution. In addition, 30 wt.% PtCo/KB-NH2 catalyst exhibited a mass activity of 535 A/gPt (H2/O2) and a rated power density of 1.05 W/cm2 at 0.67 V (H2/air), meeting the DOE targets.

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Wang, Darui, Bing Ma, Bo Wang, Chen Zhao et Peng Wu. « One-pot synthesized hierarchical zeolite supported metal nanoparticles for highly efficient biomass conversion ». Chemical Communications 51, n^o 82 (2015) : 15102–5. http://dx.doi.org/10.1039/c5cc06212h.

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Farmer, Gavin, James Abraham, Chris Littler, A. J. Syllaios et U. Philipose. « Growth of Highly-Ordered Metal Nanoparticle Arrays in the Dimpled Pores of an Anodic Aluminum Oxide Template ». Nanomaterials 12, n^o 22 (8 novembre 2022) : 3929. http://dx.doi.org/10.3390/nano12223929.

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A reliable, scalable, and inexpensive technology for the fabrication of ordered arrays of metal nanoparticles with large areal coverage on various substrates is presented. The nanoparticle arrays were formed on aluminum substrates using a two-step anodization process. By varying the anodization potential, the pore diameter, inter-pore spacing, and pore ordering in the anodic aluminum oxide (AAO) template were tuned. Following a chemical etch, the height of the pores in the AAO membrane were reduced to create a dimpled membrane surface. Periodic arrays of metal nanoparticles were subsequently created by evaporating metal on to the dimpled surface, allowing for individual nanoparticles to form within the dimples by a solid state de-wetting process induced by annealing. The ordered nanoparticle array could then be transferred to a substrate of choice using a polymer lift-off method. Following optimization of the experimental parameters, it was possible to obtain cm2 coverage of metal nanoparticles, like gold and indium, on silicon, quartz and sapphire substrates, with average sizes in the range of 50–90 nm. The de-wetting process was investigated for a specific geometry of the dimpled surface and the results explained for two different film thicknesses. Using a simple model, the experimental results were interpreted and supported by numerical estimations.

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Egan-Morriss, Christopher, Richard L. Kimber, Nigel A. Powell et Jonathan R. Lloyd. « Biotechnological synthesis of Pd-based nanoparticle catalysts ». Nanoscale Advances 4, n^o 3 (2022) : 654–79. http://dx.doi.org/10.1039/d1na00686j.

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Cell supported Pd metal nanoparticles are sustainably synthesised via microbial bioreduction. Bio-Pd nanoparticles are effective heterogeneous catalysts that catalyse industrially important reactions, such as hydrogenation and C–C coupling reactions.

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Larichev, Yurii V. « Experience of Using DLS to Study the Particle Sizes of Active Component in the Catalysts Based on the Oxide and Non-Oxide Supports ». Inorganics 10, n^o 12 (8 décembre 2022) : 248. http://dx.doi.org/10.3390/inorganics10120248.

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The present study reports the use of the dynamic light scattering (DLS) method to analyze metal nanoparticle sizes in supported catalysts (as a model system for different metal-oxide nanocomposites, ceramics, etc.). The selective dissolution of matrices has been used to transform solids to sols for DLS analysis. DLS/STS (from solid to sol) technique was tested on a wide number of different sets of supported metal catalysts (Pt, Pd, Ru metals and Al2O3, SiO2, TiO2, C3N4, carbon and polymers as supports). The transmission electron microscopy and X-ray diffraction (TEM/XRD) results for the initial supported catalysts and the DLS results for the sols prepared from them showed good agreement with each other. Moreover, it has been shown that this approach can identify the minor contamination of catalysts by large particles or aggregates which are difficult to detect by TEM/XRD.

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Kuzman, Sanja, Jovana Periša, Vesna Đorđević, Ivana Zeković, Ivana Vukoje, Željka Antić et Miroslav D. Dramićanin. « Surface Plasmon Enhancement of Eu3+ Emission Intensity in LaPO4/Ag Nanoparticles ». Materials 13, n^o 14 (10 juillet 2020) : 3071. http://dx.doi.org/10.3390/ma13143071.

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A promising way to improve the performance of luminescent materials is to combine them with noble metal nanoparticles. Herein, a set of silver/europium-doped lanthanum orthophosphate (Ag/La0.95Eu0.05PO4) nanostructures with different concentrations of silver nanoparticles were prepared and investigated. The presented overlap between the strongest europium (Eu3+) excitation line and the broad silver nanoparticle surface plasmon resonance makes the combination prospective for coupling. X-ray powder diffraction confirmed the monoclinic monazite structure. The transmission electron microscopy revealed particles with a rod-like shape and ~4 aspect ratio. Photoluminescence spectra show characteristic Eu3+ ion red emission. One of the requirements for an enhanced luminescence effect is the precise control of the distance between the noble metal nanoparticles and the emitter ion. The distance is indirectly varied throughout the change of Ag nanoparticle concentration in the La0.95Eu0.05PO4 host. The emission intensity increases with the increase in Ag nanoparticles up to 0.6 mol %, after which the luminescence decreases due to the nanoparticles’ close packing and aggregation leading to the displacement of La0.95Eu0.05PO4 from the vicinity of the metal particles and reabsorption of the emitted light. The emission intensity of La0.95Eu0.05PO4 increases more than three times when the Eu3+ excitation is supported by the localized surface plasmon resonance in the Ag/La0.95Eu0.05PO4 nanostructures.

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Lee, Jin Ah, Won Jun Lee, Joonwon Lim et Sang Ouk Kim. « N-Dopant-Mediated Growth of Metal Oxide Nanoparticles on Carbon Nanotubes ». Nanomaterials 11, n^o 8 (22 juillet 2021) : 1882. http://dx.doi.org/10.3390/nano11081882.

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Metal oxide nanoparticles supported on heteroatom-doped graphitic surfaces have been pursued for several decades for a wide spectrum of applications. Despite extensive research on functional metal oxide nanoparticle/doped carbon nanomaterial hybrids, the role of the heteroatom dopant in the hybridization process of doped carbon nanomaterials has been overlooked. Here, the direct growth of MnOx and RuOx nanoparticles in nitrogen (N)-doped sites of carbon nanotubes (NCNTs) is presented. The quaternary nitrogen (NQ) sites of CNTs actively participate in the nucleation and growth of the metal nanoparticles. The evenly distributed NQ nucleation sites mediate the generation of uniformly dispersed <10 nm diameter MnOx and RuOx nanoparticles, directly decorated on NCNT surfaces. The electrochemical performance of the resultant hybridized materials was evaluated using cyclic voltammetry. This novel hybridization method using the dopant-mediated nucleation and growth of metal oxides suggests ways that heteroatom dopants can be utilized to optimize the structure, interface and corresponding properties of graphitic carbon-based hybrid materials.

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Wiederrecht, Gary P., et Alexander Govorov. « (Digital Presentation) Characterization of Ultrafast Dynamics of Refractory Metal Nanoparticles of Interest as Photocatalysts ». ECS Meeting Abstracts MA2022-01, n^o 36 (7 juillet 2022) : 1583. http://dx.doi.org/10.1149/ma2022-01361583mtgabs.

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Plasmonic noble metal nanoparticles are of interest as photocatalysts for several reasons, including a very large absorption cross section and the creation of a greatly enhanced evanescent electromagnetic field at the surface of the nanoparticles when excited at the plasmon resonance. Furthermore, the plasmon resonance is tunable over a wide wavelength range as a function of the size, shape, and composition of the nanoparticles. When these properties are combined with the known photocatalytic activity of noble metals for technologically important targets such as solar fuels, it is not surprising that these nanoparticle systems are widely studied. Noble metals do, however, possess a weakness in that they can be easily melted upon photoexcitation, due to the fact that noble metals dissipate absorbed photon energy efficiently through ultrafast electron-phonon coupling, in roughly one picosecond, to produce heat. As a result, the study of new classes of plasmonic materials, such as refractory metals, with much higher melting points than noble metals is growing rapidly. While there are still challenges in the size-selective synthesis of refractory metal nanoparticles, characterization efforts on these materials are of strong interest. We report here a study on the time-resolved spectroscopy of electron-phonon coupling in refractory metal nanoparticles. There are very significant variations in the efficiency and time-scales of electron-phonon coupling in refractory metal nanoparticles as compared to noble metal nanoparticles. Furthermore, due to the fact that many refractory metals are oxidized under ambient conditions to create a thin oxide layer on the surface of the nanoparticles, these materials also demonstrate dynamics related to electron injection from the metal to the oxide layer that noble metals do not show. Far from being a negative, the added electron injection dynamics offer new opportunities for photocatalysis that we discuss. Use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

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Peiris, Sunari, John McMurtrie et Huai-Yong Zhu. « Metal nanoparticle photocatalysts : emerging processes for green organic synthesis ». Catalysis Science & ; Technology 6, n^o 2 (2016) : 320–38. http://dx.doi.org/10.1039/c5cy02048d.

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Metal nanoparticles (Au, Ag, Cu, Pd, Pt, Ir, Rh, Au–Pd alloyetc.) supported on inert support (ZrO₂, zeolite) can be direct photocatalysts to series of organic synthesis with visible light irradiation.

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Qiu, Bo, Xin Xiao, Min Zhang, Yue Mao et Xiaoheng Liu. « Noble metal enhanced photocatalytic activity of heterostructured TiO2 spheres with tunable interiors and shells ». Functional Materials Letters 13, n^o 08 (novembre 2020) : 2050039. http://dx.doi.org/10.1142/s1793604720500393.

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Heterostructured TiO2 spheres with tunable interiors and shells were prepared by self-template technology. This structure is composed of a hollow shell and an inner core which can enhance light scattering in the hollow space and provide a large surface to generate sufficient active sites. Besides, the nanosheets grown on the shell layer not only increased their specific surface area, but also exposed more surface-active sites. The performance of photocatalysts was estimated by the RhB decolorization, and experimental results show that the photoactivity can be greatly improved by depositing noble metal nanoparticles. It improves the efficiency of charge utilization and enhances the overall catalytic performance from the three stages of charge carrier generation, separation and surface reaction. The strong metal–support interaction (SMSI) between the noble metal nanoparticles and the oxide support has been proven to inhibit the supported precious metal, one strategy for nanoparticle aggregation and growth. On the one hand, the nanoshells isolate the precious metal nanoparticles from each other, preventing the aggregation of metal nanoparticles.

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Librando, Ivy L., Abdallah G. Mahmoud, Sónia A. C. Carabineiro, M. Fátima C. Guedes da Silva, Francisco J. Maldonado-Hódar, Carlos F. G. C. Geraldes et Armando J. L. Pombeiro. « Heterogeneous Gold Nanoparticle-Based Catalysts for the Synthesis of Click-Derived Triazoles via the Azide-Alkyne Cycloaddition Reaction ». Catalysts 12, n^o 1 (31 décembre 2021) : 45. http://dx.doi.org/10.3390/catal12010045.

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A supported gold nanoparticle-catalyzed strategy has been utilized to promote a click chemistry reaction for the synthesis of 1,2,3-triazoles via the azide-alkyne cycloaddition (AAC) reaction. While the advent of effective non-copper catalysts (i.e., Ru, Ag, Ir) has demonstrated the catalysis of the AAC reaction, additional robust catalytic systems complementary to the copper catalyzed AAC remain in high demand. Herein, Au nanoparticles supported on Al2O3, Fe2O3, TiO2 and ZnO, along with gold reference catalysts (gold on carbon and gold on titania supplied by the World Gold Council) were used as catalysts for the AAC reaction. The supported Au nanoparticles with metal loadings of 0.7–1.6% (w/w relative to support) were able to selectively obtain 1,4-disubstituted-1,2,3-triazoles in moderate yields up to 79% after 15 min, under microwave irradiation at 150 °C using a 0.5–1.0 mol% catalyst loading through a one-pot three-component (terminal alkyne, organohalide and sodium azide) procedure according to the “click” rules. Among the supported Au catalysts, Au/TiO2 gave the best results.

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Guerra-Balcázar, M., J. Torres-González, I. Terol-Villalobos, J. Morales-Hernández et F. Castañeda. « Glassy Carbon Electrode-Supported Au Nanoparticles for the Glucose Electrooxidation : On the Role of Crystallographic Orientation ». Journal of Nanomaterials 2012 (2012) : 1–8. http://dx.doi.org/10.1155/2012/387581.

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Glucose electrooxidation in alkaline solution was examined using glassy carbon electrodes modified with Au nanoparticles. Au nanoparticles were prepared following the two-phase protocol and characterized by transmission electron microscopy (TEM), UV-Vis spectroscopy, X-ray diffraction spectroscopy (XRD), and cyclic voltammetry (CV). It was found that, under the study conditions, it is possible to obtain nanoparticles between 1 and 5 nm; also it was found that the crystallographic orientation is strongly influenced by the ratio metal/thiol and to a lesser extent by the synthesis temperature. The voltammetric response for the electrocatalytic oxidation of glucose at carbon Au nanoparticle-modified electrode shows an increasing activity with nanoparticles size. Electroactivity and possibly selectivity are found to be nanoparticles' crystallographic orientation dependent. Classical electrochemical analysis shows that glucose electrooxidation is a diffusion-controlled process followed by a homogenous reaction.

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Rabah, Mahmoud A. « Recovery of Nanoparticles of Metal Values from Spent Metallized Graphite Brushes and Slip Rings ». Advanced Materials Research 1101 (avril 2015) : 203–7. http://dx.doi.org/10.4028/www.scientific.net/amr.1101.203.

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This work provides a method to recover monolayer metal values having nanoparticle in size from spent metalized graphite brushes. The recovered metals are supported on porous glassy carbon substrate by chemical or electro deposition process. The chemical method involves crushing and grinding of the spent brushes to pass 200 mesh. Magnetic separation removed magnetic susceptible metals such as iron. Nonferrous metals were leached using 3N nitric acid in hot conditions. Hydroxide gel of the dissolved metals generated with 1N ammonium hydroxide. The carbon substrate was multi-impregnated with metals hydroxide 3-4 times. In each time, the loaded carbon was dried. Free metals on the carbon substrate are obtained by reducing the hydroxide with hydrazine hydrate or by thermal reduction using hydrogen gas at 900°C. In the electro deposition process, ground spent brushes were packed in a polyethylene cloth used as anode. The electrolyte is 3M of sulfate salt of the metal of concern. Pulse current cyclic voltmetric technique was applied to control the particle diameter and thickness of the deposited metal. Results revealed that monolayer silver and copper of nanoparticles has been successfully prepared from spent metalized graphite brushes. Electro deposition is more friendly environment procedure and more convenient, less cost and more precise.

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Shesterkina, Anastasiya A., Anna A. Strekalova, Elena V. Shuvalova, Gennady I. Kapustin, Olga P. Tkachenko et Leonid M. Kustov. « CuO-Fe2O3 Nanoparticles Supported on SiO2 and Al2O3 for Selective Hydrogenation of 2-Methyl-3-Butyn-2-ol ». Catalysts 11, n^o 5 (12 mai 2021) : 625. http://dx.doi.org/10.3390/catal11050625.

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In this study, novel SiO2- and Al2O3-supported Cu-Fe catalysts are developed for selective hydrogenation of 2-methyl-3-butyne-2-ol to 2-methyl-3-butene-2-ol under mild reaction conditions. TEM, XRD, and FTIR studies of adsorbed CO and TPR-H2 are performed to characterize the morphology, nanoparticle size, and particle distribution, as well as electronic state of deposited metals in the prepared catalysts. The deposition of Fe and Cu metal particles on the aluminum oxide carrier results in the formation of a mixed oxide phase with a strong interaction between the Fe and Cu precursors during the calcination. The highly dispersed nanoparticles of Fe2O3 and partially reduced CuOx, with an average size of 3.5 nm and with strong contact interactions between the metals in 5Cu-5Fe/Al2O3 catalysts, provide a high selectivity of 93% toward 2-methyl-3-butene-2-ol at complete conversion of the unsaturated alcohol.

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Wang, Hanfei, Dan Liu et Chunli Xu. « Directed synthesis of well dispersed and highly active AuCu and AuNi nanoparticle catalysts ». Catalysis Science & ; Technology 6, n^o 19 (2016) : 7137–50. http://dx.doi.org/10.1039/c6cy00799f.

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Schmidt, Tobias, Rodrigo Q. Albuquerque, Rhett Kempe et Stephan Kümmel. « Investigating the electronic structure of a supported metal nanoparticle : Pd in SiCN ». Physical Chemistry Chemical Physics 18, n^o 46 (2016) : 31966–72. http://dx.doi.org/10.1039/c6cp06520a.

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Wang, Zhaoxi, Yanli Chen, Wei Yan et Yuanzhuang Cheng. « Solid-phase preparation of defective carbon supported PtNi alloy electrocatalyst and analysis of its oxygen reduction mechanism ». Journal of Physics : Conference Series 2383, n^o 1 (1 décembre 2022) : 012133. http://dx.doi.org/10.1088/1742-6596/2383/1/012133.

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In the present work, PtNi-loaded defective carbon (Pt/ZnPPC) was prepared by solid-phase method. Carbon support with specific defect types, such as Zn metal nitrogen carbon (ZnPPC850), N-doped carbon (ZnPPC950) and defective carbon (ZnPPC1050), were selectively obtained by optimizing the pyrolysis temperature to explore the effect of defect types on oxygen reduction reactions (ORR). Electrochemical measurements showed that the half-wave potential of the PtNi metal nanoparticle-loaded ZnPPC1050 catalyst (PtNi-ZnPPC1050) outperformed the commercial JM-Pt/C by 35 mV, and by 45 mV compared to the PtNi-loaded ZnPPC950 catalyst (PtNi-ZnPPC950), suggesting that the defects in the ZnPPC1050 support resulting from the evaporation of N by pyrolysis can interact well with Pt metal electrically, allowing the PtNi nanoparticles to be uniformly distributed. Meanwhile, the defects lead to the carrier containing a large number of active sites making its catalytic performance even much better than the pyridine nitrogen sites in ZnPPC950. The carbon defect structure is loosened and porous with high specific surface area, which can effectively load PtNi nanoparticles and enhance the mass transfer. We obtained a new bimetallic oxygen reduction catalyst loaded with PtNi on defective carbon and elucidated the effect of five-membered ring carbon defect structure and N-doped structure on metal-carrier interaction.

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Sims, Christopher M., Audaldo A. Ponce, Karen J. Gaskell et Bryan W. Eichhorn. « CO tolerance of Pt and PtSn intermetallic electrocatalysts on synthetically modified reduced graphene oxide supports ». Dalton Transactions 44, n^o 3 (2015) : 977–87. http://dx.doi.org/10.1039/c4dt02544j.

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Electrochemical studies demonstrated the ability to modify the catalytic activities of graphene supported Pt and PtSn nanoparticle electrocatalysts by altering the nature of the metal-support interactions.

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Lugo-José, Yuliana K., John R. Monnier, Andreas Heyden et Christopher T. Williams. « Hydrodeoxygenation of propanoic acid over silica-supported palladium : effect of metal particle size ». Catal. Sci. Technol. 4, n^o 11 (2014) : 3909–16. http://dx.doi.org/10.1039/c4cy00605d.

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Brzezinska, Magdalena, Johannes Niemeier, Yannik Louven, Nicolas Keller, Regina Palkovits et Agnieszka M. Ruppert. « TiO2 supported Ru catalysts for the hydrogenation of succinic acid : influence of the support ». Catalysis Science & ; Technology 10, n^o 20 (2020) : 6860–69. http://dx.doi.org/10.1039/d0cy01446j.

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Mesgarzadeh, Iraj, Ali Reza Akbarzadeh, Rahmatollah Rahimi et Ali Maleki. « Novel Design, Preparation, Characterization and Antimicrobial Activity of Silver Nanoparticles during Oak Acorns Bark Retrograde ». Zeitschrift für Physikalische Chemie 232, n^o 2 (23 février 2018) : 209–21. http://dx.doi.org/10.1515/zpch-2017-0970.

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AbstractIn search for a probable local solution for Qarasu River problems and based on our prescience about metal ion chelating/reducing ability of tannins which are found in large amount in oak acorns bark, Quercus brantii (Persian oak) acorns bark extract was exploited as reducing/capping agent in silver nanoparticles synthesis. Synthesis was carried out as a single-step method at room temperature, and without consuming any external energy by using these renewable barks. The crystallinity, size and shape of the nanoparticles were characterized by X-ray diffraction and scanning electron microscopy (SEM) respectively. The involvement of phenolic compounds in metal ion reduction was supported by UV-Visible and infrared spectroscopies and by acidity and conductivity measurements. The SEM-based particle size distribution analysis and antimicrobial susceptibility test of oak acorns bark-extract-mediated silver nanoparticles against bacterial effluent were pointed out to the critical proportion of silver salt to the capping/reducing agent. It seems that the bactericidal action depends on the extent to which accumulation of silver nanoparticle (Ag-Np) in bacterial cell surface alters the silver nanoparticle colloidal stability in broth medium.

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Johnson, Robert L., Frédéric A. Perras, Takeshi Kobayashi, Thomas J. Schwartz, James A. Dumesic, Brent H. Shanks et Marek Pruski. « Identifying low-coverage surface species on supported noble metal nanoparticle catalysts by DNP-NMR ». Chemical Communications 52, n^o 9 (2016) : 1859–62. http://dx.doi.org/10.1039/c5cc06788j.

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Ding, Ya, et Xing-Hua Xia. « Preparation and Characterization of Hollow Carbon Nanospheres Supported Metallic Catalysts by Using One-Step Pyrolysis Method ». Journal of Nanoscience and Nanotechnology 8, n^o 3 (1 mars 2008) : 1512–17. http://dx.doi.org/10.1166/jnn.2008.18219.

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A versatile one-step pyrolysis method is successfully employed to fabricate hollow carbon nanospheres (HCNs, ca. 60 nm in diameter) supported with metallic nanoparticle catalyst. The resultant catalyst hybrid was characterized by using TEM, FTIR, TGA measurements. It is confirmed that, as the carbon precursor and hollow core/shell structure template, hollow chitosan nanospheres provide the important adsorption sites for the metallic precursor. The one-step pyrolysis process at 750 °C under nitrogen atmosphere results in the simultaneous decomposition of the chitosan nanospheres to HCNs and the adsorbed metal salt complex to metallic nanoparticles. It is found that metallic nanoparticles with an average diameter of ca. 4 nm highly dispersed in the carbon shell of HCNs, and no aggregation phenomenon occurs under the high deposition temperature. As a demonstration, the HCNs-supported Pt catalyst for the electrochemical methanol oxidation was studied.

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Sarnello, Erik, Zheng Lu, Soenke Seifert, Randall E. Winans et Tao Li. « Design and Characterization of ALD-Based Overcoats for Supported Metal Nanoparticle Catalysts ». ACS Catalysis 11, n^o 5 (11 février 2021) : 2605–19. http://dx.doi.org/10.1021/acscatal.0c05099.

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Nugroho, Ferry A. A., Beniamino Iandolo, Jakob B. Wagner et Christoph Langhammer. « Bottom-Up Nanofabrication of Supported Noble Metal Alloy Nanoparticle Arrays for Plasmonics ». ACS Nano 10, n^o 2 (5 février 2016) : 2871–79. http://dx.doi.org/10.1021/acsnano.5b08057.

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An, Hyeun Hwan, Seung Jae Lee, Hee-Soo Kim, Won Bae Han et Chong Seung Yoon. « Structure of solid-supported lipid membrane probed by noble metal nanoparticle deposition ». Biochimica et Biophysica Acta (BBA) - Biomembranes 1818, n^o 11 (novembre 2012) : 2884–91. http://dx.doi.org/10.1016/j.bbamem.2012.07.006.

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Li, Zhe-Fei, Yuxuan Wang et Gerardine G. Botte. « Revisiting the electrochemical oxidation of ammonia on carbon-supported metal nanoparticle catalysts ». Electrochimica Acta 228 (février 2017) : 351–60. http://dx.doi.org/10.1016/j.electacta.2017.01.020.

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Deng, Shao Xin, Hu Wang et Tie Hong Chen. « Solvent-Free Aerobic Oxidation of Benzyl Alcohol by Resin Supported Noble Metal Catalysts ». Advanced Materials Research 466-467 (février 2012) : 234–37. http://dx.doi.org/10.4028/www.scientific.net/amr.466-467.234.

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Noble metal nanoparticle catalysts supported by resin were prepared by a simple adsorption method. Resin D261 is an organic polymer containing quaternary ammonium group. The specific interaction between quaternary ammonium groups and different kinds of noble metal precursors can be generally applied for the preparation of supported noble metal catalysts. Due to the specific interaction, an easy control of the loading of noble metal can be achieved. Furthermore, without using volatile organic solvents and calcinations in the preparation procedure, the method reported here is environmentally benign and economically feasible. The catalysts were tested in aerobic oxidation of benzyl alcohol to benzaldehyde under solvent- and base-free conditions and exhibited high activity and excellent selectivity.

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MURATSUGU, Satoshi, et Mizuki TADA. « Creation of Supported Metal Complex, Metal Nanoparticle, and Metal Oxide Catalysts and Operando Synchrotron Radiation X-ray Analyses ». Vacuum and Surface Science 65, n^o 5 (10 mai 2022) : 230–35. http://dx.doi.org/10.1380/vss.65.230.

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Song, Yingji, Xuefeng Chu, Yingzi Lin et Xiaotian Yang. « Pyrrolidone Modifying Gold Nanocatalysts for Enhanced Catalytic Activities in Aerobic Oxidation of Alcohols and Carbon Monoxide ». Journal of Chemistry 2017 (2017) : 1–8. http://dx.doi.org/10.1155/2017/5257296.

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Enhancing the catalytic activity of supported metal nanoparticle is a great demand but extremely challenging to make. We reported a simple strategy for enhancing the activities by employing the polyvinylpyrrolidone (PVP) additive, where a series of supported Au nanoparticle catalysts including Au/C, Au/BN, Au/TiO2, and Au/SBA-15 exhibited significantly higher activities in the oxidation of various alcohols and carbon monoxide by molecular oxygen after adding PVP to the reaction system. The XPS study indicates that PVP could electronically interact with Au to form high active Au sites for molecular oxygen, thus causing improved activities for the various oxidation reactions.

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Fatimah, Is, Ganjar Fadillah, Ika Yanti et Ruey-an Doong. « Clay-Supported Metal Oxide Nanoparticles in Catalytic Advanced Oxidation Processes : A Review ». Nanomaterials 12, n^o 5 (1 mars 2022) : 825. http://dx.doi.org/10.3390/nano12050825.

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Advanced oxidation processes (AOPs) utilizing heterogeneous catalysts have attracted great attention in the last decade. The use of solid catalysts, including metal and metal oxide nanoparticle support materials, exhibited better performance compared with the use of homogeneous catalysts, which is mainly related to their stability in hostile environments and recyclability and reusability. Various solid supports have been reported to enhance the performance of metal and metal oxide catalysts for AOPs; undoubtedly, the utilization of clay as a support is the priority under consideration and has received intensive interest. This review provides up-to-date progress on the synthesis, features, and future perspectives of clay-supported metal and metal oxide for AOPs. The methods and characteristics of metal and metal oxide incorporated into the clay structure are strongly influenced by various factors in the synthesis, including the kind of clay mineral. In addition, the benefits of nanomaterials from a green chemistry perspective are key aspects for their further considerations in various applications. Special emphasis is given to the basic schemes for clay modifications and role of clay supports for the enhanced mechanism of AOPs. The scaling-up issue is suggested for being studied to further applications at industrial scale.

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Trigoura, Leslie, Yalan Xing et Bhanu P. S. Chauhan. « Recyclable Catalysts for Alkyne Functionalization ». Molecules 26, n^o 12 (9 juin 2021) : 3525. http://dx.doi.org/10.3390/molecules26123525.

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In this review, we present an assessment of recent advances in alkyne functionalization reactions, classified according to different classes of recyclable catalysts. In this work, we have incorporated and reviewed the activity and selectivity of recyclable catalytic systems such as polysiloxane-encapsulated novel metal nanoparticle-based catalysts, silica–copper-supported nanocatalysts, graphitic carbon-supported nanocatalysts, metal organic framework (MOF) catalysts, porous organic framework (POP) catalysts, bio-material-supported catalysts, and metal/solvent free recyclable catalysts. In addition, several alkyne functionalization reactions have been elucidated to demonstrate the success and efficiency of recyclable catalysts. In addition, this review also provides the fundamental knowledge required for utilization of green catalysts, which can combine the advantageous features of both homogeneous (catalyst modulation) and heterogeneous (catalyst recycling) catalysis.

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Arias-Madrid, Daniela, Oscar E. Medina, Jaime Gallego, Sócrates Acevedo, Alexander A. Correa-Espinal, Farid B. Cortés et Camilo A. Franco. « NiO, Fe2O3, and MoO3 Supported over SiO2 Nanocatalysts for Asphaltene Adsorption and Catalytic Decomposition : Optimization through a Simplex–Centroid Mixture Design of Experiments ». Catalysts 10, n^o 5 (19 mai 2020) : 569. http://dx.doi.org/10.3390/catal10050569.

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The main objective of this study was to evaluate the effect of functionalized silica nanoparticles with Fe2O3, NiO, and MoO3 metal oxides on the decomposition of asphaltenes, through an experimental simplex–centroid mixture design for surface area, asphaltene adsorption, and activation energy. The experimental nanoparticle surface area was measured by adsorption of N2. Adsorption isotherms, and the subsequent oxidation process of asphaltenes, were performed through batch adsorption experiments and thermogravimetric analysis, respectively. Among the monometallic systems, the presence of iron increased the affinity between the nanoparticle and the asphaltenes, and a higher metal oxide load increased the adsorptive capacity of the system. For the pairings evaluated, there was better synergy between iron and nickel, with the participation of the former being slightly superior. In the mixture design that included three transition elements, the participation of molybdenum was not significant, and the adsorption of asphaltenes was dominated by the active sites formed by the other two transition element oxides. The mixture design created to minimize the activation energy showed that the interaction of the three transition elements is important and can be evidenced in the interaction coefficients.

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Lindenthal, Lorenz, Raffael Rameshan, Harald Summerer, Thomas Ruh, Janko Popovic, Andreas Nenning, Stefan Löffler, Alexander Karl Opitz, Peter Blaha et Christoph Rameshan. « Modifying the Surface Structure of Perovskite-Based Catalysts by Nanoparticle Exsolution ». Catalysts 10, n^o 3 (1 mars 2020) : 268. http://dx.doi.org/10.3390/catal10030268.

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In heterogeneous catalysis, surfaces decorated with uniformly dispersed, catalytically-active (nano)particles are a key requirement for excellent performance. Beside standard catalyst preparation routines—with limitations in controlling catalyst surface structure (i.e., particle size distribution or dispersion)—we present here a novel time efficient route to precisely tailor catalyst surface morphology and composition of perovskites. Perovskite-type oxides of nominal composition ABO3 with transition metal cations on the B-site can exsolve the B-site transition metal upon controlled reduction. In this exsolution process, the transition metal emerges from the oxide lattice and migrates to the surface where it forms catalytically active nanoparticles. Doping the B-site with reducible and catalytically highly active elements, offers the opportunity of tailoring properties of exsolution catalysts. Here, we present the synthesis of two novel perovskite catalysts Nd0.6Ca0.4FeO3-δ and Nd0.6Ca0.4Fe0.9Co0.1O3-δ with characterisation by (in situ) XRD, SEM/TEM and XPS, supported by theory (DFT+U). Fe nanoparticle formation was observed for Nd0.6Ca0.4FeO3-δ. In comparison, B site cobalt doping leads, already at lower reduction temperatures, to formation of finely dispersed Co nanoparticles on the surface. These novel perovskite-type catalysts are highly promising for applications in chemical energy conversion. First measurements revealed that exsolved Co nanoparticles significantly improve the catalytic activity for CO2 activation via reverse water gas shift reaction.

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Wojciechowska, Joanna, Elisa Gitzhofer, Jacek Grams, Agnieszka Ruppert et Nicolas Keller. « Solar Light Induced Photon-Assisted Synthesis of TiO2 Supported Highly Dispersed Ru Nanoparticle Catalysts ». Materials 11, n^o 11 (19 novembre 2018) : 2329. http://dx.doi.org/10.3390/ma11112329.

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Ru/TiO2 are promising heterogeneous catalysts in different key-reactions taking place in the catalytic conversion of biomass towards fuel additives, biofuels, or biochemicals. TiO2 supported highly dispersed nanometric-size metallic Ru catalysts were prepared at room temperature via a solar light induced photon-assisted one-step synthesis in liquid phase, far smaller Ru nanoparticles with sharper size distribution being synthesized when compared to the catalysts that were prepared by impregnation with thermal reduction in hydrogen. The underlying strategy is based on the redox photoactivity of the TiO2 semi-conductor support under solar light for allowing the reduction of metal ions pre-adsorbed at the host surface by photogenerated electrons from the conduction band of the semi-conductor in order to get a fine control in terms of size distribution and dispersion, with no need of chemical reductant, final thermal treatment, or external hydrogen. Whether acetylacetonate or chloride was used as precursor, 0.6 nm sub-nanometric metallic Ru particles were synthesized on TiO2 with a sharp size distribution at a low loading of 0.5 wt.%. Using the chloride precursor was necessary for preparing Ru/TiO2 catalysts with a 0.8 nm sub-nanometric mean particle size at 5 wt.% loading, achieved in basic conditions for benefitting from the enhanced adsorption between the positively-charged chloro-complexes and the negatively-charged TiO2 surface. Remarkably, within the 0.5–5 wt.% range, the Ru content had only a slight influence on the sub-nanometric particle size distribution, thanks to the implementation of suitable photo-assisted synthesis conditions. We demonstrated further that a fine control of the metal Ru nanoparticle size on the TiO2 support was possible via a controlled nanocluster growth under irradiation, while the nanoparticles revealed a good resistance to thermal sintering.

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Kim, Yu-Jin, Jaeyoung Lee, Gwang-Bum Im, Jihun Song, Jiwoo Song, Jiyong Chung, Taekyung Yu et Suk Ho Bhang. « Dual Ion Releasing Nanoparticles for Modulating Osteogenic Cellular Microenvironment of Human Mesenchymal Stem Cells ». Materials 14, n^o 2 (15 janvier 2021) : 412. http://dx.doi.org/10.3390/ma14020412.

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In this study we developed a dual therapeutic metal ion-releasing nanoparticle for advanced osteogenic differentiation of stem cells. In order to enhance the osteogenic differentiation of human mesenchymal stem cells (hMSCs) and induce angiogenesis, zinc (Zn) and iron (Fe) were synthesized together into a nanoparticle with a pH-sensitive degradation property. Zn and Fe were loaded within the nanoparticles to promote early osteogenic gene expression and to induce angiogenic paracrine factor secretion for hMSCs. In vitro studies revealed that treating an optimized concentration of our zinc-based iron oxide nanoparticles to hMSCs delivered Zn and Fe ion in a controlled release manner and supported osteogenic gene expression (RUNX2 and alkaline phosphatase) with improved vascular endothelial growth factor secretion. Simultaneous intracellular release of Zn and Fe ions through the endocytosis of the nanoparticles further modulated the mild reactive oxygen species generation level in hMSCs without cytotoxicity and thus improved the osteogenic capacity of the stem cells. Current results suggest that our dual ion releasing nanoparticles might provide a promising platform for future biomedical applications.

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