Effect of Gold Electronic State on the Catalytic Performance of Nano Gold Catalysts in n-Octanol Oxidation
| Autor: | Ekaterina Pakrieva, Yulia Kotolevich, Mario H. Farías, D. A. Pichugina, Nina Bogdanchikova, Sónia A. C. Carabineiro, N.A. Nikitina, Laura Pascual, Vicente Cortés Corberán, A. N. Kharlanov, E. Kolobova, Trino Armando Zepeda Partida, Hugo J. Tiznado Vazquez, Dmitrii German, Alexey Pestryakov |
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| Přispěvatelé: | LAQV@REQUIMTE, DQ - Departamento de Química, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Russian Foundation for Basic Research, Tomsk Polytechnic University |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Materials science
gold catalysts General Chemical Engineering Solvent adsorption Inorganic chemistry Energy-dispersive X-ray spectroscopy acid-base centers DFT Article Catalysis Pretreatment atmosphere lcsh:Chemistry Adsorption X-ray photoelectron spectroscopy Gold active sites Materials Science(all) Desorption support modifiers General Materials Science N-octanol oxidation Selectivity gold electronic state Spectroscopy Acid-base centers Gold catalysts Gold electronic state n-octanol oxidation selectivity pretreatment atmosphere lcsh:QD1-999 Colloidal gold Chemical Engineering(all) solvent adsorption metal content Metal content Brønsted–Lowry acid–base theory Support modifiers gold active sites |
| Zdroj: | Nanomaterials, Vol 10, Iss 880, p 880 (2020) Nanomaterials Digital.CSIC. Repositorio Institucional del CSIC instname Repositório Científico de Acesso Aberto de Portugal Repositório Científico de Acesso Aberto de Portugal (RCAAP) instacron:RCAAP Volume 10 Issue 5 |
| ISSN: | 2079-4991 |
| Popis: | This study aims to identify the role of the various electronic states of gold in the catalytic behavior of Au/MxOy/TiO2 (where MxOy are Fe2O3 or MgO) for the liquid phase oxidation of n-octanol, under mild conditions. For this purpose, Au/MxOy/TiO2 catalysts were prepared by deposition-precipitation with urea, varying the gold content (0.5 or 4 wt.%) and pretreatment conditions (H2 or O2), and characterized by low temperature nitrogen adsorption-desorption, X-ray powder diffraction (XRD), energy dispersive spectroscopy (EDX), scanning transmission electron microscopy-high angle annular dark field (STEM HAADF), diffuse reflectance Fourier transform infrared (DRIFT) spectroscopy of CO adsorption, temperature-programmable desorption (TPD) of ammonia and carbon dioxide, and X-ray photoelectron spectroscopy (XPS). Three states of gold were identified on the surface of the catalysts, Au0, Au1+ and Au3+, and their ratio determined the catalysts performance. Based on a comparison of catalytic and spectroscopic results, it may be concluded that Au+ was the active site state, while Au0 had negative effect, due to a partial blocking of Au0 by solvent. Au3+ also inhibited the oxidation process, due to the strong adsorption of the solvent and/or water formed during the reaction. Density functional theory (DFT) simulations confirmed these suggestions. The dependence of selectivity on the ratio of Brønsted acid centers to Brønsted basic centers was revealed. This work was partially supported by the Associate Laboratory for Green Chemistry—LAQV, and financed by national funds from FCT/MCTES (UIDB/50006/2020)(Portugal), Tomsk Polytechnic University Competitiveness Enhancement Program, project VIU-RSCBMT-65/2019 and Russian Foundation of Basic Research, project 18-29-24037 (Russia), and MINECO project CTQ2017-86170-R (Spain). |
| Databáze: | OpenAIRE |
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