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Effects of Support on the Formation and Activity of Gold Catalysts for Ethanol Conversion to Butanol
https://orcid.org/http://orcid.org/0000-0002-9091-3537
https://orcid.org/http://orcid.org/0000-0002-4443-7998
https://orcid.org/http://orcid.org/0000-0002-3251-7181
https://orcid.org/http://orcid.org/0000-0003-2218-8254
https://orcid.org/http://orcid.org/0000-0002-3387-9248
https://orcid.org/http://orcid.org/0000-0002-7151-6317
https://orcid.org/http://orcid.org/0000-0002-8253-2945
Using a combination of physicochemical methods, such as TEM, SEM, EDS, XPS, NH3–TPD, and N2 adsorption, the study investigates the structure of a number of supports (Al2O3, SiO2, TiO2, ZrO2, and C) and of Au/support catalyst samples (Au = 0.5%). The concentration of highly active 2–4 nm gold particles in Au catalysts is influenced by the support’s texture; this concentration increases in the following order: Au/TiO2 < Au/ZrO2 < Au/C < Au/SiO2 << Au/Al2O3. The acidity of Au catalysts is influenced by the support’s nature; this acidity decreases in the following order: Al2O3 > TiO2 > ZrO2 > SiO2 >> Au/C. At 275°C, a carbon support is inactive in ethanol conversion to butanol. In the presence of oxide supports, the target reaction occurs at a relatively low rate by a bimolecular condensation mechanism. Over Au/Al2O3, Au/SiO2, Au/TiO2, or Au/ZrO2, the reaction occurs more rapidly by an aldol condensation mechanism. At an ethanol conversion of 14–18%, the butanol selectivity increases in the following order: Au/C(0) << Au/SiO2 (0.4%) < Au/ZrO2 (1.5%) < Au/TiO2 (2%) << Au/Al2O3 (78%). The high efficiency of Au/Al2O3 stems from the high density of the Aln+–O2– sites located on the support’s surface, and of the coordination-unsaturated Au0(KH) atoms located on the surface of 2–4 nm gold particles.
Effects of Support on the Formation and Activity of Gold Catalysts for Ethanol Conversion to Butanol
https://orcid.org/http://orcid.org/0000-0002-9091-3537
https://orcid.org/http://orcid.org/0000-0002-4443-7998
https://orcid.org/http://orcid.org/0000-0002-3251-7181
https://orcid.org/http://orcid.org/0000-0003-2218-8254
https://orcid.org/http://orcid.org/0000-0002-3387-9248
https://orcid.org/http://orcid.org/0000-0002-7151-6317
https://orcid.org/http://orcid.org/0000-0002-8253-2945
Using a combination of physicochemical methods, such as TEM, SEM, EDS, XPS, NH3–TPD, and N2 adsorption, the study investigates the structure of a number of supports (Al2O3, SiO2, TiO2, ZrO2, and C) and of Au/support catalyst samples (Au = 0.5%). The concentration of highly active 2–4 nm gold particles in Au catalysts is influenced by the support’s texture; this concentration increases in the following order: Au/TiO2 < Au/ZrO2 < Au/C < Au/SiO2 << Au/Al2O3. The acidity of Au catalysts is influenced by the support’s nature; this acidity decreases in the following order: Al2O3 > TiO2 > ZrO2 > SiO2 >> Au/C. At 275°C, a carbon support is inactive in ethanol conversion to butanol. In the presence of oxide supports, the target reaction occurs at a relatively low rate by a bimolecular condensation mechanism. Over Au/Al2O3, Au/SiO2, Au/TiO2, or Au/ZrO2, the reaction occurs more rapidly by an aldol condensation mechanism. At an ethanol conversion of 14–18%, the butanol selectivity increases in the following order: Au/C(0) << Au/SiO2 (0.4%) < Au/ZrO2 (1.5%) < Au/TiO2 (2%) << Au/Al2O3 (78%). The high efficiency of Au/Al2O3 stems from the high density of the Aln+–O2– sites located on the support’s surface, and of the coordination-unsaturated Au0(KH) atoms located on the surface of 2–4 nm gold particles.
Effects of Support on the Formation and Activity of Gold Catalysts for Ethanol Conversion to Butanol
https://orcid.org/http://orcid.org/0000-0002-9091-3537
https://orcid.org/http://orcid.org/0000-0002-4443-7998
https://orcid.org/http://orcid.org/0000-0002-3251-7181
https://orcid.org/http://orcid.org/0000-0003-2218-8254
https://orcid.org/http://orcid.org/0000-0002-3387-9248
https://orcid.org/http://orcid.org/0000-0002-7151-6317
https://orcid.org/http://orcid.org/0000-0002-8253-2945
Using a combination of physicochemical methods, such as TEM, SEM, EDS, XPS, NH3–TPD, and N2 adsorption, the study investigates the structure of a number of supports (Al2O3, SiO2, TiO2, ZrO2, and C) and of Au/support catalyst samples (Au = 0.5%). The concentration of highly active 2–4 nm gold particles in Au catalysts is influenced by the support’s texture; this concentration increases in the following order: Au/TiO2 < Au/ZrO2 < Au/C < Au/SiO2 << Au/Al2O3. The acidity of Au catalysts is influenced by the support’s nature; this acidity decreases in the following order: Al2O3 > TiO2 > ZrO2 > SiO2 >> Au/C. At 275°C, a carbon support is inactive in ethanol conversion to butanol. In the presence of oxide supports, the target reaction occurs at a relatively low rate by a bimolecular condensation mechanism. Over Au/Al2O3, Au/SiO2, Au/TiO2, or Au/ZrO2, the reaction occurs more rapidly by an aldol condensation mechanism. At an ethanol conversion of 14–18%, the butanol selectivity increases in the following order: Au/C(0) << Au/SiO2 (0.4%) < Au/ZrO2 (1.5%) < Au/TiO2 (2%) << Au/Al2O3 (78%). The high efficiency of Au/Al2O3 stems from the high density of the Aln+–O2– sites located on the support’s surface, and of the coordination-unsaturated Au0(KH) atoms located on the surface of 2–4 nm gold particles.
Effects of Support on the Formation and Activity of Gold Catalysts for Ethanol Conversion to Butanol
Pet. Chem.
Nikolaev, S. A. (author) / Chistyakov, A. V. (author) / Chistyakova, P. A. (author) / Ezzhelenko, D. I. (author) / Liberman, E. Yu. (author) / Konkova, T. V. (author) / Tsodikov, M. V. (author)
Petroleum Chemistry ; 61 ; 748-761
2021-07-01
14 pages
Article (Journal)
Electronic Resource
English
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