Academic literature on the topic 'Surface interaction, photoelectron spectroscopy, catalysis'

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Journal articles on the topic "Surface interaction, photoelectron spectroscopy, catalysis"

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Yoon, Ji Sun, Min Bum Park, Youngmin Kim, Dong Won Hwang, and Ho-Jeong Chae. "Effect of Metal Oxide–Support Interactions on Ethylene Oligomerization over Nickel Oxide/Silica–Alumina Catalysts." Catalysts 9, no. 11 (November 8, 2019): 933. http://dx.doi.org/10.3390/catal9110933.

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We investigated the interactions between nickel oxide and silica–alumina supports, which were applied to the catalytic oligomerization of ethylene by powder X-ray diffraction, UV diffuse reflectance spectroscopy, H2 temperature-programmed reduction, and X-ray photoelectron spectroscopy. The catalytic activity was also correlated with the acidity of catalysts determined by NH3 temperature-programmed desorption and pyridine FT-IR spectroscopy. Although all the catalysts had similar Ni contents, their catalytic performances were strongly influenced by the strength of the metal oxide–support interaction. Strong interaction promoted the formation of nickel aluminate on the catalyst surface, and resulted in low catalytic activity due to reducing the amount of nickel oxide active sites. However, weak interaction favored the aggregation of nickel oxide species into larger particles, and thus resulted in low ethylene conversion and selectivity to oligomers. Eventually, the optimal activity was realized at the medium interaction strength, preserving a high amount of both active nickel oxides and acid sites.
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Charisiou, Nikolaos, Savvas Douvartzides, Georgios Siakavelas, Lazaros Tzounis, Victor Sebastian, Vlad Stolojan, Steven Hinder, Mark Baker, Kyriaki Polychronopoulou, and Maria Goula. "The Relationship between Reaction Temperature and Carbon Deposition on Nickel Catalysts Based on Al2O3, ZrO2 or SiO2 Supports during the Biogas Dry Reforming Reaction." Catalysts 9, no. 8 (August 9, 2019): 676. http://dx.doi.org/10.3390/catal9080676.

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The tackling of carbon deposition during the dry reforming of biogas (BDR) necessitates research of the surface of spent catalysts in an effort to obtain a better understanding of the effect that different carbon allotropes have on the deactivation mechanism and correlation of their formation with catalytic properties. The work presented herein provides a comparative assessment of catalytic stability in relation to carbon deposition and metal particle sintering on un-promoted Ni/Al2O3, Ni/ZrO2 and Ni/SiO2 catalysts for different reaction temperatures. The spent catalysts were examined using thermogravimetric analysis (TGA), Raman spectroscopy, high angle annular dark field scanning transmission electron microscopy (STEM-HAADF) and X-ray photoelectron spectroscopy (XPS). The results show that the formation and nature of carbonaceous deposits on catalytic surfaces (and thus catalytic stability) depend on the interplay of a number of crucial parameters such as metal support interaction, acidity/basicity characteristics, O2– lability and active phase particle size. When a catalytic system possesses only some of these beneficial characteristics, then competition with adverse effects may overshadow any potential benefits.
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El-Salamony, Radwa A., Ahmed S. Al-Fatesh, Kenit Acharya, Abdulaziz A. M. Abahussain, Abdulaziz Bagabas, Nadavala Siva Kumar, Ahmed A. Ibrahim, Wasim Ullah Khan, and Rawesh Kumar. "Carbon Dioxide Valorization into Methane Using Samarium Oxide-Supported Monometallic and Bimetallic Catalysts." Catalysts 13, no. 1 (January 4, 2023): 113. http://dx.doi.org/10.3390/catal13010113.

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Samarium oxide (Sm2O3) is a versatile surface for CO2 and H2 interaction and conversion. Samarium oxide-supported Ni, samarium oxide-supported Co-Ni, and samarium oxide-supported Ru-Ni catalysts were tested for CO2 methanation and were characterized by X-ray diffraction, nitrogen physisorption, infrared spectroscopy, H2-temperature programmed reduction, and X-ray photoelectron spectroscopy. Limited H2 dissociation and widely available surface carbonate and formate species over 20 wt.% Ni, dispersed over Sm2O3, resulted in ~98% CH4 selectivity. The low selectivity for CO could be due to the reforming reaction between CH4 (methanation product) and CO2. Co-impregnation of cobalt with nickel over Sm2O3 had high surface adsorbed oxygen and higher CO selectivity. On the other hand, co-impregnation of ruthenium and nickel over Sm2O3 led to more than one catalytic active site, carbonate species, lack of formate species, and 94% CH4 selectivity. It indicated the following route of CH4 synthesis over Ru-Ni/Sm2O3; carbonate → unstable formate → CO → CH4.
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Todorova, Silviya, Anton Naydenov, Maya Shopska, Hristo Kolev, Iliyana Yordanova, and Krasimir Tenchev. "Pt-Modified Nano-Sized Mn2O3 Oxide Prepared from the Mn3O4 Phase with Tetragonal Symmetry for CO Oxidation." Symmetry 14, no. 12 (December 1, 2022): 2543. http://dx.doi.org/10.3390/sym14122543.

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One of the current problems in the environmental catalysis is the design of an effective and less costly catalytic system for the oxidation of CO. The nano-sized α-Mn2O3 oxide has been prepared and modified with 0.5 wt.% Pt. The catalysts have been characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), temperature-programmed reduction (TPR) and diffuse-reflectance infrared spectroscopy (DRIFTS). Finely divided PtO and Pt(OH)2 are being formed on the Mn2O3 surface as a result of the strong interaction between platinum and the nano-oxide. Based on DRIFTS investigations and the model calculations, a Langmuir–Hinshelwood type of mechanism is supposed for CO oxidation on Pt/Mn2O3. The CO and oxygen are adsorbed on different types of sites. The Mars–van Krevelen mechanism is the most probable one over pure Mn2O3, thus suggesting that CO2 is adsorbed on the oxidized sites. The CO adsorption in the mixture CO + N2 or in the presence of oxygen (CO + N2 + O2) leads to a partial reduction in the Pt+ surface species and the formation of linear Pt1+−CO and Pt0−CO carbonyls. Both of them take part in the CO oxidation reaction.
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Siemer, Michael, Lars Mohrhusen, Maximilian Grebien, and Katharina Al-Shamery. "Amine Capped Gold Colloids at Oxidic Supports: Their Electronic Interactions." Zeitschrift für Physikalische Chemie 233, no. 1 (December 19, 2018): 69–84. http://dx.doi.org/10.1515/zpch-2018-0004.

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Abstract Colloidal deposition of noble metal nanoparticles on oxidic supports is a recent approach for the fabrication of heterogeneous catalyst materials. We present studies on the interaction of different amine ligands with gold nanoparticles before and after deposition on several oxidic supports (titania, silica, alumina, magnesia or zinc oxide), using X-ray photoelectron and Auger spectroscopy, and high-resolution transmission electron microscopy. The adsorption of amines on thin gold films as well as on nanoparticles leads to a decrease in metal photoelectron binding energies. Usually, this is explained by donor-acceptor interactions via the amine group. By additional analysis of Auger signals, which are more sensitive to changes in the oxidation state than photoelectron spectra, we demonstrate that these shifts are due to a final state effect, namely, the increased photoelectron hole screening in presence of amine adsorbates. It will be shown, that this effect is not sensitive neither to the nanoparticle size nor the sterical properties of the capping amine. After deposition on oxide supports, the photoelectron binding energies are even further decreased. The presented findings exhibit that care has to be taken to interpret binding energy shifts simply with charging, which has impact on understanding the local electronic situation on the surface of metal-loaded oxides, crucial for heterogeneous catalysis.
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Chuai, Hongyuan, Penghe Su, Hongchi Liu, Baolin Zhu, Shoumin Zhang, and Weiping Huang. "Alkali and Alkaline Earth Cation-Decorated TiO2 Nanotube-Supported Rh Catalysts for Vinyl Acetate Hydroformylation." Catalysts 9, no. 2 (February 20, 2019): 194. http://dx.doi.org/10.3390/catal9020194.

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Alkali and alkaline earth cation-decorated TiO2 nanotube (TNT)-supported rhodium catalysts were synthesized and characterized by inductively-coupled plasma optical emission spectrometer, surface characterization analyzer, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier transforming infrared spectrum, respectively. Their catalytic performances were evaluated by the hydroformylation of vinyl acetate. Results showed that both the conversion rate of vinyl acetate and selectivity for aldehyde were improved after Rh/TNTs were modified by alkali or alkali-earth cations. Such improved selectivity for aldehyde might be attributed to the presence of alkali or alkaline earth cations which enhanced CO adsorption, while the high conversion rate of vinyl acetate was likely due to the proper interaction of Lewis acid–base between cations modified TNTs and vinyl acetate.
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Zhao, Feng, Shuangde Li, Xiaofeng Wu, Renliang Yue, Weiman Li, Xicuo Zha, Yuzhou Deng, and Yunfa Chen. "Catalytic Behaviour of Flame-Made CuO-CeO2 Nanocatalysts in Efficient CO Oxidation." Catalysts 9, no. 3 (March 13, 2019): 256. http://dx.doi.org/10.3390/catal9030256.

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CuO-CeO2 nanocatalysts with varying CuO contents (1, 5, 9, 14 and 17 wt %) were prepared by one-step flame spray pyrolysis (FSP) and applied to CO oxidation. The influences of CuO content on the as-prepared catalysts were systematically characterized by X-ray diffraction (XRD), N2 adsorption-desorption at −196 °C, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and hydrogen-temperature programmed reduction (H2-TPR). A superior CO oxidation activity was observed for the 14 wt % CuO-CeO2 catalyst, with 90% CO conversion at 98 °C at space velocity (60,000 mL × g−1 × h−1), which was attributed to abundant surface defects (lattice distortion, Ce3+, and oxygen vacancies) and high reducibility supported by strong synergistic interaction. In addition, the catalyst also displayed excellent stability and resistance to water vapor. Significantly, in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) showed that in the CO catalytic oxidation process, the strong synergistic interaction led readily to dehydroxylation and CO adsorption on Cu+ at low temperature. Furthermore, in the feed of water vapor, although there was an adverse effect on the access of CO adsorption, there was also a positive effect on the formation of fewer carbon intermediates. All these results showed the potential of highly active and water vapor-resistive CuO-CeO2 catalysts prepared by FSP.
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Fazlikeshteli, Shiva, Xavier Vendrell, and Jordi Llorca. "Low-Temperature Methane Partial Oxidation over Pd Supported on CeO2: Effect of the Preparation Method and Precursors." Reactions 2, no. 1 (February 17, 2021): 30–42. http://dx.doi.org/10.3390/reactions2010004.

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The catalytic production of syngas by the partial oxidation of methane (POM) was investigated over Pd supported on ceria (0.5–2 Pd wt.%) prepared by incipient wetness impregnation and by mechanochemical methods. The performance of the Pd/CeO2 catalyst prepared by milling CeO2 and Pd acetate was superior to that prepared by milling CeO2 and Pd nitrate and to Pd/CeO2 prepared by impregnation from Pd acetate. The best catalytic activity of the Pd/CeO2 catalyst prepared from CeO2 and Pd acetate was obtained by milling at 50 Hz for 5 min. Two-step combustion and reforming reaction mechanism were identified. Remarkably, methane conversion increased progressively with Pd loading for the catalysts prepared by incipient wetness impregnation, whereas low metal loading showed better conversion of methane for the catalysts prepared by ball milling using Pd acetate. This was explained in terms of an impressive dispersion of Pd species with a strong interaction with the surface of ceria, as deduced from transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy characterization, which revealed a large quantity of highly oxidized species at the surface.
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Filip, Mihaela, Elena Maria Anghel, Vasile Rednic, Florica Papa, Simona Somacescu, Cornel Munteanu, Nicolae Aldea, Jing Zhang, and Viorica Parvulescu. "Variation in Metal–Support Interaction with TiO2 Loading and Synthesis Conditions for Pt-Ti/SBA-15 Active Catalysts in Methane Combustion." Nanomaterials 13, no. 10 (May 15, 2023): 1647. http://dx.doi.org/10.3390/nano13101647.

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The control of catalytic performance using synthesis conditions is one of the main goals of catalytic research. Two series of Pt-Ti/SBA-15 catalysts with different TiO2 percentages (n = 1, 5, 10, 30 wt.%) were obtained from tetrabutylorthotitanate (TBOT) and peroxotitanate (PT), as titania precursors and Pt impregnation. The obtained catalysts were characterized using X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM), N2 sorption, Raman, X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), hydrogen temperature-programmed reduction (H2-TPR) and H2-chemisorption measurements. Raman spectroscopy showed framework titanium species in low TiO2 loading samples. The anatase phase was evidenced for samples with higher titania loading, obtained from TBOT, and a mixture of rutile and anatase for those synthesized by PT. The rutile phase prevails in rich TiO2 catalysts obtained from PT. Variable concentrations of Pt0 as a result of the stronger interaction of PtO with anatase and the weaker interaction with rutile were depicted using XPS. TiO2 loading and precursors influenced the concentration of Pt species, while the effect on Pt nanoparticles’ size and uniform distribution on support was insignificant. The Pt/PtO ratio and their concentration on the surface were the result of strong metal–support interaction, and this influenced catalytic performance in the complete oxidation of methane at a low temperature. The highest conversion was obtained for sample prepared from PT with 30% TiO2.
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Kong, Weimin, Shuyuan Zhou, Xuwei Wang, Qingrong He, Piaoping Yang, Ye Yuan, and Yanchun Dong. "Catalytic Oxidative Decomposition of Dimethyl Methyl Phosphonate over CuO/CeO2 Catalysts Prepared Using a Secondary Alkaline Hydrothermal Method." Catalysts 12, no. 10 (October 19, 2022): 1277. http://dx.doi.org/10.3390/catal12101277.

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Bimetallic synergism plays an important role in lattice-doped catalysts. Therefore, lattice-doped bimetallic CuO/CeO2 catalysts were prepared by secondary alkaline hydrothermal reaction. During this process, the CeO2 nanomaterials were partially dissolved and recrystallized; thus, Cu ions were doped into the CeO2 lattice. The physical and chemical properties of CeO2, CuO/CeO2, and CuO were investigated. H2 temperature-programmed reduction characterization showed that the oxidation activity of CuO/CeO2 was significantly improved. X-ray photoelectron spectroscopy results showed that electron transfer occurred between Ce and Cu in the CuO/CeO2 catalyst. Additionally, Raman characterization confirmed the strong interaction between Cu and Ce. After CuO was loaded, the thermal catalytic decomposition performance of the catalyst was significantly improved with respect to the sarin simulant dimethyl methyl phosphonate (DMMP); with an increase in the Cu/Ce ratio, the performance first strengthened and then weakened. Additionally, the reaction tail gas and catalyst surface products were analyzed using mass spectrometry and ion chromatography, and the changes in the surface products during the thermal catalytic decomposition of DMMP were characterized at different temperatures using in situ diffuse reflectance infrared Fourier transform spectroscopy. Finally, the catalytic reaction pathways of DMMP on CeO2, CuO/CeO2, and CuO were inferred. The study results not only demonstrate an effective catalyst for the removal of nerve agent but also a feasible preparation method for lattice-doped bimetallic catalysts in the field of environmental protection.
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Dissertations / Theses on the topic "Surface interaction, photoelectron spectroscopy, catalysis"

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Back, Tyson Cody. "SURFACE CHEMISTRY OF METAL CATALYST UNDER CARBON NANOTUBE GROWTH CONDITIONS." University of Dayton / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1272935820.

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Peronio, Angelo. "A closer look at heterogeneous catalysis: reaction intermediates at the single-molecule level." Doctoral thesis, Università degli studi di Trieste, 2013. http://hdl.handle.net/10077/8577.

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2011/2012
The present work pertains to the surface science approach to heterogeneous catalysis. In particular model systems for CO2 hydrogenation to methanol, and NO selective catalytic reduction, are investigated by means of a combined approach, where the molecular-level insight provided by a low-temperature scanning tunneling microscope is complemented by density functional theory (DFT) calculations of their electronic structure. To this end, the Inelastic Electron Tunneling Spectroscopy (STM-IETS) technique was introduced for the first time in our laboratory, a recent development which allows to measure the vibrational spectrum of individual molecules adsorbed on a surface. Regarding CO2, we provide single molecule imaging and characterization of CO2/Ni(110), chemisorbed with high charge transfer from the substrate, in an activated state that plays a crucial role in the hydrogenation process. We obtain a detailed characterization of the adsorption geometries and an estimate of the energies corresponding to the different adsorbed states. A consistent picture of CO2 chemisorption on Ni(110) is provided on the basis of the newly available information, yielding a deeper insight into the previously existing spectroscopic and theoretical data. In the Selective Catalytic Reduction (SCR) process, nitrogen oxide is selectively transformed to N2 by reductants such as ammonia. The specificity of this reaction was tentatively attributed to the formation of NH3-NO coadsorption complexes, as indicated by several surface science techniques. Here we characterize the NH3-NO complex at the atomic scale on the (111) surface of platinum, investigating the intermolecular interactions that tune the selectivity. The structures that arise upon coadsorption of NH3 and NO are analyzed in terms of adsorption sites, geometry, energetics and charge rearrangement. An ordered 2 × 2 adlayer forms, where the two molecules are arranged in a configuration that maximizes mutual interactions. In this structure, NH3 adsorbs on top and NO on fcc-hollow sites, leading to a cohesional stabilization of the extended layer by 0.29 eV/unit cell. The calculated vibrational energies of the individually-adsorbed species and of the coadsorption structure fit the experimental values found in literature within less than 6%. The characterizations and optimizations that had to be tackled in order to successfully perform STM-IETS measurement are eventually presented, focusing in particular on an original method which allows to increase the achieved resolution. Namely, the modulation broadening associated to phase-sensitive detection is reduced by employing a tailored modulation function, different from the commonly-used sinusoid. This method is not limited to STM-IETS, but can be easily applied whenever a lock-in amplifier is used to measure a second derivative.
XXV Ciclo
1984
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(5930045), Cory A. Milligan. "FUNDAMENTAL INSIGHTS OF PLANAR AND SUPPORTED CATALYSTS." Thesis, 2019.

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A fundamental understanding of heterogeneous catalysis requires analysis of model catalytic surfaces in tandem with complex technical catalysts. This work was divided in three areas, 1- preparation and characterization of model surfaces synthesized by vapor deposition techniques, 2- kinetic evaluation of model catalysts for formic acid decomposition and dry methane reforming, 3- characterization and kinetic evaluation of technical catalysts for the water gas shift reaction.

In the first project, model PdZn intermetallic surfaces, a relevant catalyst for propane dehydrogenation, were prepared using an ALD approach. In this work, model surfaces were synthesized by exposing Pd(111) and Pd(100) surfaces to diethylzinc at ca. 10-6 mbar. Several different surface structures were identified by careful control of the deposition temperature of the substrate. Modifications in the adsorption properties of these surfaces towards carbon monoxide and propylene coincided with the structure of the PdZn surface layer.

In the second project, formic acid decomposition kinetics were evaluated on model Pt catalysts. Formic acid decomposition was found to be structure-insensitive on Pt(111), Pt(100), and a polycrystalline foil under standard reaction conditions. CO selectivity remained < 1% for conversions <10%. Additionally, inverse Pd-Zr model catalysts were prepared by ALD of zirconium-t-butoxide (ZTB). Depending on treatment conditions, either ZrOxHy or ZrO2 overlayers or Zr as sub-nanometer clusters could be obtained. The activity of the model catalyst surface towards dry reforming of methane if the initial state of the zirconium is metallic.

In the third project, Au/Fe3O4 heterodimer catalysts were characterized for their thermal stability. In-situ TEM and XPS characterization demonstrates that the gold nanoparticles transform into gold thin films that wet the Fe3O4 surface as the reduction of the oxide proceeds. DFT calculations show that the adhesion energy between the Au film is increased on a partially reduced Fe3O4 surface. Additionally, Pt/Nb2CTx catalysts were characterized and kinetics evaluated for the water gas shift reaction. XPS and TEM characterization indicates that a Pt-Nb surface alloy is formed under moderate reduction temperatures, 350OC. Water-gas shift reaction kinetics reveal that the alloy-MXene interface exhibit high H2O activation ability compared to a non-reducible support or bulk niobium carbide.

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Bach, Markus. "Fundamental Analysis of the Interaction of Low Pressure Plasmas with Polymer Surfaces." Doctoral thesis, 2003. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2003112531.

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The treatment of polymer surfaces by low pressure plasmas is of technological interest in a variety of applications for modification and functionalisation. Until now the interactions of the individual plasma species (especially electrons) with polymeric material have not been subject of a microscopic study.In an anticipated chapter the inner plasma parameters were characterised by Langmuir probe measurements, leading to a precise knowledge about the density and energy distributions of plasma electrons and ions. The values for electrons were later used for an exclusive treatment with this species. The main part of this thesis describes and interprets the chemical composition after UV, plasma and electron treatment by x-ray photoelectron spectroscopy (XPS), structural changes by atomic force microscopy (AFM) and their combination to distinguish the fundamental interactions with polyethylene and polypropylene surfaces. It was found that all treatments show specific modification behaviour according to the chemical composition, topography and modification depth. For an argon microwave discharge, the plasma effects can also be obtained by a combination of UV and electron treatment. Fundamental radical reactions have been traced indirectly by chemical derivatisation as well as their passivation reactions through cross-linkage and the creation of double bonds.
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Books on the topic "Surface interaction, photoelectron spectroscopy, catalysis"

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McGovern, Mark Edward. Monolayer chemistry - interaction of OTS with quartz/glass surfaces in various solvents probed by x-ray photoelectron spectroscopy and surface acoustic wave device. Ottawa: National Library of Canada, 1993.

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Book chapters on the topic "Surface interaction, photoelectron spectroscopy, catalysis"

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Mun, Bongjin Simon, Hiroshi Kondoh, Zhi Liu, Phil N. Ross, and Zahid Hussain. "The Development of Ambient Pressure X-Ray Photoelectron Spectroscopy and Its Application to Surface Science." In Current Trends of Surface Science and Catalysis, 197–229. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-8742-5_9.

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Goldmann, A. "Chapter 5: Photoelectron Spectroscopy." In Studies in Surface Science and Catalysis, 160–95. Elsevier, 1987. http://dx.doi.org/10.1016/s0167-2991(09)60454-7.

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Lee, Adam F., Christopher M. A. Parlett, and Karen Wilson. "X-Ray Photoelectron Spectroscopy." In Contemporary Catalysis: Science, Technology, and Applications, 496–512. The Royal Society of Chemistry, 2017. http://dx.doi.org/10.1039/9781849739900-00496.

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X-ray photoelectron spectroscopy (XPS) is a key tool for the quantitative analysis of surface composition and oxidation state, and universally employed in academic and commercial settings to improve the design of heterogeneous catalysts. This section outlines the principles and application of XPS as a versatile, chemically specific analytical tool to determine the electronic structure and near surface composition of constituent elements within industrially relevant catalytic materials.
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"Appendix B XPS X-ray photoelectron spectroscopy." In Studies in Surface Science and Catalysis, 501–4. Elsevier, 1995. http://dx.doi.org/10.1016/s0167-2991(06)81524-7.

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Lee, Adam F., Karen Wilson, and Richard M. Lambert. "In situ observation of a surface catalysed chemical reaction by fast X-ray photoelectron spectroscopy." In Studies in Surface Science and Catalysis, 3095–100. Elsevier, 2000. http://dx.doi.org/10.1016/s0167-2991(00)80497-8.

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Heber, M., and W. Grünert. "Characterization of adsorbates and surface functional groups on polycrystalline oxides by ultraviolet photoelectron spectroscopy (UPS)." In Studies in Surface Science and Catalysis, 3279–84. Elsevier, 2000. http://dx.doi.org/10.1016/s0167-2991(00)80528-5.

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Borade, Ramesh B., and Abraham Clearfield. "Probing Acid Sites in Zeolites by X-ray Photoelectron Spectroscopy Using Pyridine as a Probe Molecule." In Studies in Surface Science and Catalysis, 661–68. Elsevier, 1994. http://dx.doi.org/10.1016/s0167-2991(08)64171-3.

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Spevack, P. A., L. L. Coatsworth, N. S. Mcintyre, I. Schmidt, and J. R. Brown. "A Miniature On-Line Closed-Cycle Reactor for X-Ray Photoelectron Spectroscopy Studies of Hydrodesulphurization Reactions." In Studies in Surface Science and Catalysis, 229–42. Elsevier, 1989. http://dx.doi.org/10.1016/s0167-2991(08)60501-7.

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De Jong, K. P., H. P. C. E. Kuipers, and J. A. R. Van Veen. "Topology of Coke Deposits in Spent Heavy Oil Processing Catalysts. A Quantitative X-Ray Photoelectron Spectroscopy Study." In Studies in Surface Science and Catalysis, 289–96. Elsevier, 1991. http://dx.doi.org/10.1016/s0167-2991(08)62646-4.

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Molina, R., M. Genet, and G. Poncelet. "A X-ray photoelectron spectroscopy investigation of α-alumina-supported nickel catalysts prepared from nickel (II) acetylacetonate." In Studies in Surface Science and Catalysis, 3333–38. Elsevier, 2000. http://dx.doi.org/10.1016/s0167-2991(00)80537-6.

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Conference papers on the topic "Surface interaction, photoelectron spectroscopy, catalysis"

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Hertel, T., E. Knoesel, M. Wolf, and G. Ertl. "Time-Resolved Two-Colour Photoelectron Spectroscopy of Clean and Adsorbate Covered Metal Surfaces." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/up.1996.fe.45.

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The dynamics of photoexcited electrons and their interaction with adsorbates is of fundamental importance for many photostimulated reactions at metal surfaces. Such reactions are frequently mediated by 'hot' substrate electrons and the corresponding reaction cross sections will, therefore, depend critically on the charge carrier dynamics in the near surface region. On the other hand the perturbation of the local electronic structure by an adsorbate may allow to alter lifetimes of electronically excited states at surfaces.
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Moser, Eva Maria, Sidney Chappuis, and Javier Olleros. "Photocatalytically Active Titania Produced by MOCVD Plasma Process." In 13th International Conference on Plasma Surface Engineering September 10 - 14, 2012, in Garmisch-Partenkirchen, Germany. Linköping University Electronic Press, 2013. http://dx.doi.org/10.3384/wcc2.321-324.

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The deposition of photocatalytically active titania layers at ambient temperature was developed using the plasma enhanced metal organic chemical vapour deposition (PE-MOCVD) method at low and atmospheric pressure. An increase of the photo-activity in the near ultraviolet (UV) and blue light irradiation was achieved by doping the titania layers using the elements nitrogen and/or carbon. Investigation of the chemical and structural features of the titania layers was carried out by x-ray photoelectron spectroscopy, atomic force microscopy, and Raman. The optical energy bandgap and photocatalytic activity at 365/428 nm for various titania layers were analyzed using ellipsometry and the methylene blue dye bleaching according to ISO 10678:2010, respectively. The reduction of the aqueous methylene blue solution was similar for the two categories of titania layers. However, the photo-induced properties such as the mineralization of stearic acid for investigating anti-fingerprint effects evidenced a weaker interaction between the mostly hydrophobic PE-MOCVD titania surfaces than for the hydrophilic and rougher PVD produced titania layers when irradiated under UV light. The observed differences were related to the chemical and structural features since the hydrophobic PE-MOCVD produced titania layers were amorphous and nitrogen and carbon incorporation into TiO2 led to an enhanced photocatalytic ability by a factor of two regarding the dye tests, whereas the energy bandgap remained at about 3.2 eV. Substitutional and interstitial doping of nitrogen and/or carbon was evidenced by XPS. An additional benefit regarding the adhesion and abrasion resistance was observed for the tailored doping of titania layers.
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Liu, Y. S., H. S. Cole, and H. R. Philipp. "Interactions of excimer lasers with polymers." In International Laser Science Conference. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/ils.1986.fb2.

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Interaction of high photon energy (> 5-eV) radiation from excimer lasers with polymeric materials has drawn much interest because of its potential importance in material processing such as etching and patterning which have found use over a number of diversified fields such as medicine, polymer science, and microelectronics. The laser etching process is noncontact, maskless, selective, and offers a high spatial resolution. Although the topic has been the subject of numerous recent studies, basic parameters for understanding interactions between polymers and high energy photons are not well understood. In this paper we present the results of a recent study on VUV optical properties of several polymeric materials including polymethyl methacrylate (PMMA), polystyrene (PS), polyvinylacetate (PVA), polyimide (PI), and polycarbonate (PC) and review parameters that are critical for understanding the interaction of polymers with excimer laser radiation. Results of a study of the surface compostions using small area x-ray photoelectron spectroscopy of two kinds of polymer, PMMA and PS, irradiated with an ArF laser at a photon energy of 6.4 eV are discussed. A simple model is then presented to show how various parameters including optical constants, photon energy, laser fluence, and polymer structures affect characteristics of photon etching observed in these polymers.
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4

Chai, Rukaun, Yuetian Liu, Qianjun Liu, Xuan He, and Pingtian Fan. "Effect and Mechanism of CO2 Electrochemical Reduction for CCUS-EOR." In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/206135-ms.

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Abstract Unconventional reservoir plays an increasingly important role in the world energy system, but its recovery is always quite low. Therefore, the economic and effective enhanced oil recovery (EOR) technology is urgently required. Moreover, with the aggravation of greenhouse effect, carbon neutrality has become the human consensus. How to sequestrate CO2 more economically and effectively has aroused wide concerns. Carbon Capture, Utilization and Storage (CCUS)-EOR is a win-win technology, which can not only enhance oil recovery but also increase CO2 sequestration efficiency. However, current CCUS-EOR technologies usually face serious gas channeling which finally result in the poor performance on both EOR and CCUS. This study introduced CO2 electrochemical conversion into CCUS-EOR, which successively combines CO2 electrochemical reduction and crude oil electrocatalytic cracking both achieves EOR and CCUS. In this study, multiscale experiments were conducted to study the effect and mechanism of CO2 electrochemical reduction for CCUS-EOR. Firstly, the catalyst and catalytic electrode were synthetized and then were characterized by using scanning electron microscope (SEM) & energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Then, electrolysis experiment & liquid-state nuclear magnetic resonance (1H NMR) experiments were implemented to study the mechanism of CO2 electrochemical reduction. And electrolysis experiment & gas chromatography (GC) & viscosity & density experiments were used to investigate the mechanism of crude oil electrocatalytic cracking. Finally, contact angle and coreflooding experiments were respectively conducted to study the effect of the proposed technology on wettability and CCUS-EOR. SEM & EDS & XPS results confirmed that the high pure SnO2 nanoparticles with the hierarchical, porous structure, and the large surface area were synthetized. Electrolysis & 1H NMR experiment showed that CO2 has converted into formate with the catalysis of SnO2 nanoparticles. Electrolysis & GC & Density & Viscosity experiments indicated that the crude oil was electrocatalytically cracked into the light components (&lt;C20) from the heavy components (C21∼C37). As voltage increases from 2.0V to 7.0V, the intensity of CO2 electrocchemical reduction and crude oil electrocatalytic cracking enhances to maximum at 3.5V (i.e., formate concentration reaches 6.45mmol/L and carbon peak decreases from C17 to C15) and then weakens. Contact angle results indicated that CO2 electrochemical reduction and crude oil electocatalytic cracking work jointly to promote wettability alteration. Thereof, CO2 electrochemical reduction effect is dominant. Coreflooding results indicated that CO2 electrochemical reduction technology has great potential on EOR and CCUS. With the SnO2 catalytic electrode at optimal voltage (3.5V), the additional recovery reaches 9.2% and CO2 sequestration efficiency is as high as 72.07%. This paper introduced CO2 electrochemical conversion into CCUS-EOR, which successfully combines CO2 electrochemical reduction and crude oil electrocatalytic cracking into one technology. It shows great potential on CCUS-EOR and more studies are required to reveal its in-depth mechanisms.
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5

Autric, Michel, Laurence Yaghdjian, Gilbert Vacquier, and Gines Nicolas. "KrF Excimer Laser Induced Modifications of Aluminum Nitride Ceramic Materials." In The European Conference on Lasers and Electro-Optics. Washington, D.C.: Optica Publishing Group, 1998. http://dx.doi.org/10.1364/cleo_europe.1998.cmb2.

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Physical and chemical transformations induced upon sintered aluminum nitride (AIN) ceramic materials under KrF excimer laser irradiation have been studied in order to improve its properties and make this advanced material interesting for microelectronic applications or high power electrical systems. Due to its high thermal conductivity (180 W.m-1.K-1 at 20 °C), its high electrical resistivity (1014 Ω.cm at 25 °C), a low thermal expansion coefficient (5.10-6 K), a high temperature resistance (sublimation temperature 2500 °C), a very high hardness (1100 Kgf.mm-2) and a relative chemical inertia, AIN is a very attractive material for industrial uses[1]. Experiments were performed using a LPX 220i KrF-248 nm- excimer laser able to deliver 0.4 J in 20 ns (FWHM) at 1-200 Hz repetition rate. Experimental conditions were chosen as following: incident fluence between 0.5 and 5 J/cm2, up to 100 shots in atmospheric pressure ambient air. The material investigated was a commercial sintered ceramic crystallized in the wurtzite structure. After irradiation, depending on the fluence level, interaction processes induce color and topography changes in the impacted areas: - a reversible one, from the initial color (white/grey) to brown-yellow at low fluence (F< 0.5 J/cm2); - a irreversible one, from white to silver-grey at higher fluence (> 1J/cm2) with roughness and porosity modifications. This last process suggests a melting and vaporization of the surface and a one-step metallization process confirmed by different surface analysis techniques [2]. A molten layer is produced in the bulk material (200 nm) and the initial roughness (0.35 μm Ra) is decreased. Auger Electron Spectroscopy, Raman Spectroscopy and X-ray Photoelectron Spectroscopy gave results on composition and chemical bondings onto the extreme surface and in the molten layer. Low incidence angle X-ray diffraction method characterized elements and structure. These analysis revealed the obtaining of a electrical conductive path onto the substrate constituted in an Aluminum-rich layer. AES showed alumina with oxygen, carbon and nitrogen on foe top characteristic of a contamination layer before irradiation; after treatment, Al2O3 appears on foe top, Al in the melted depth (after sputtering). The formation of this aluminum layer is confirmed by XPS analysis where Al peak is shifted from 78.5 to 79.7 eV. On the Ruman spectra, foe three Al-N bonds desappeared after irradiations evidencing the metallic aspect of the surface. X-Y electrical resistance measurements were performed in order to confirm this metallization process using a classical four-probes measurement head The resistance (infinite on the initial material) drops to some Ω on the irradiated area (2 J/cm2; 20-50 shots) with a very sharp transition zone (a few microns). These experiments shown it is possible to obtain a conductive path by a chemical modification of the insolating ceramic surface with a very flexible way using an excimer laser, mask projection or micromarking by a scanning system. Measurements of the electrical resistivity evolution of the aluminum-rich conductive path with time under industrial conditions (ambient air, humidity, temperature) are in progress in the laboratory.
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