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Bimetallic Gold-Silver Nanoparticles Supported on Zeolitic Imidazolate Framework-8 as Highly Active Heterogenous Catalysts for Selective Oxidation of Benzyl Alcohol into Benzaldehyde
The metal-organic zeolite imidazolate framework-8 (ZIF-8) supported gold-silver bimetallic catalysts with a core-shell structure (Au@Ag/ZIF-8 and Ag@Au/ZIF-8) and cluster structure (AuAg/ZIF-8) were successfully prepared by the deposition-redispersion method. Energy dispersive X-ray spectroscopy (ED...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6403852/ https://www.ncbi.nlm.nih.gov/pubmed/30961014 http://dx.doi.org/10.3390/polym10101089 |
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author | Liu, Lili Zhou, Xiaojing Yan, Yongmei Zhou, Jie Zhang, Wenping Tai, Xishi |
author_facet | Liu, Lili Zhou, Xiaojing Yan, Yongmei Zhou, Jie Zhang, Wenping Tai, Xishi |
author_sort | Liu, Lili |
collection | PubMed |
description | The metal-organic zeolite imidazolate framework-8 (ZIF-8) supported gold-silver bimetallic catalysts with a core-shell structure (Au@Ag/ZIF-8 and Ag@Au/ZIF-8) and cluster structure (AuAg/ZIF-8) were successfully prepared by the deposition-redispersion method. Energy dispersive X-ray spectroscopy (EDS) elemental mapping images displayed that in the Au@Ag/ZIF-8 catalyst, Ag atoms were deposited on an exposed Au surface, and core-shell structured Au@Ag particles with highly dispersed Ag as the shell were formed. Additionally, the XPS investigation at gold 4f levels and silver 3d levels indicated that the Au and Ag particles of Au@Ag/ZIF-8, Ag@Au/ZIF-8, and AuAg/ZIF-8 were in a zero valence state. Among the resultant catalysts obtained in this study, Ag@Au/ZIF-8 catalysts showed the highest catalytic activity for the selective oxidation of benzyl alcohol, followed by AuAg/ZIF-8 and Au@Ag/ZIF-8. The turnover frequency (TOF) values were in the order of Ag@Au/ZIF-8 (28.2 h(−1)) > AuAg/ZIF-8 (25.0 h(−1)) > Au@Ag/ZIF-8 (20.0 h(−1)) at 130 °C within 1 h under 8 bar O(2) when using THF as solvent. The catalysts of Au@Ag/ZIF-8 and Ag@Au/ZIF-8 with core–shell structures have higher benzaldehyde selectivities (53.0% and 53.3%) than the AuAg/ZIF-8 catalyst (35.2%) in the selective oxidation of benzyl alcohol into benzaldehyde. The effect of the solvent, reaction temperature, reaction time, and reaction pressure on benzyl alcohol conversion and benzaldehyde selectivity in benzyl alcohol selective oxidation over Au@Ag/ZIF-8, Ag@Au/ZIF-8, and AuAg/ZIF-8 were also investigated. All of the catalysts showed excellent performance at 130 °C under 8 bar O(2) within 1 h when using THF as the solvent in the selective oxidation of benzyl alcohol to benzaldehyde. Moreover, the catalysts can be easily recycled and used repetitively at least four times. |
format | Online Article Text |
id | pubmed-6403852 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-64038522019-04-02 Bimetallic Gold-Silver Nanoparticles Supported on Zeolitic Imidazolate Framework-8 as Highly Active Heterogenous Catalysts for Selective Oxidation of Benzyl Alcohol into Benzaldehyde Liu, Lili Zhou, Xiaojing Yan, Yongmei Zhou, Jie Zhang, Wenping Tai, Xishi Polymers (Basel) Article The metal-organic zeolite imidazolate framework-8 (ZIF-8) supported gold-silver bimetallic catalysts with a core-shell structure (Au@Ag/ZIF-8 and Ag@Au/ZIF-8) and cluster structure (AuAg/ZIF-8) were successfully prepared by the deposition-redispersion method. Energy dispersive X-ray spectroscopy (EDS) elemental mapping images displayed that in the Au@Ag/ZIF-8 catalyst, Ag atoms were deposited on an exposed Au surface, and core-shell structured Au@Ag particles with highly dispersed Ag as the shell were formed. Additionally, the XPS investigation at gold 4f levels and silver 3d levels indicated that the Au and Ag particles of Au@Ag/ZIF-8, Ag@Au/ZIF-8, and AuAg/ZIF-8 were in a zero valence state. Among the resultant catalysts obtained in this study, Ag@Au/ZIF-8 catalysts showed the highest catalytic activity for the selective oxidation of benzyl alcohol, followed by AuAg/ZIF-8 and Au@Ag/ZIF-8. The turnover frequency (TOF) values were in the order of Ag@Au/ZIF-8 (28.2 h(−1)) > AuAg/ZIF-8 (25.0 h(−1)) > Au@Ag/ZIF-8 (20.0 h(−1)) at 130 °C within 1 h under 8 bar O(2) when using THF as solvent. The catalysts of Au@Ag/ZIF-8 and Ag@Au/ZIF-8 with core–shell structures have higher benzaldehyde selectivities (53.0% and 53.3%) than the AuAg/ZIF-8 catalyst (35.2%) in the selective oxidation of benzyl alcohol into benzaldehyde. The effect of the solvent, reaction temperature, reaction time, and reaction pressure on benzyl alcohol conversion and benzaldehyde selectivity in benzyl alcohol selective oxidation over Au@Ag/ZIF-8, Ag@Au/ZIF-8, and AuAg/ZIF-8 were also investigated. All of the catalysts showed excellent performance at 130 °C under 8 bar O(2) within 1 h when using THF as the solvent in the selective oxidation of benzyl alcohol to benzaldehyde. Moreover, the catalysts can be easily recycled and used repetitively at least four times. MDPI 2018-10-01 /pmc/articles/PMC6403852/ /pubmed/30961014 http://dx.doi.org/10.3390/polym10101089 Text en © 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Liu, Lili Zhou, Xiaojing Yan, Yongmei Zhou, Jie Zhang, Wenping Tai, Xishi Bimetallic Gold-Silver Nanoparticles Supported on Zeolitic Imidazolate Framework-8 as Highly Active Heterogenous Catalysts for Selective Oxidation of Benzyl Alcohol into Benzaldehyde |
title | Bimetallic Gold-Silver Nanoparticles Supported on Zeolitic Imidazolate Framework-8 as Highly Active Heterogenous Catalysts for Selective Oxidation of Benzyl Alcohol into Benzaldehyde |
title_full | Bimetallic Gold-Silver Nanoparticles Supported on Zeolitic Imidazolate Framework-8 as Highly Active Heterogenous Catalysts for Selective Oxidation of Benzyl Alcohol into Benzaldehyde |
title_fullStr | Bimetallic Gold-Silver Nanoparticles Supported on Zeolitic Imidazolate Framework-8 as Highly Active Heterogenous Catalysts for Selective Oxidation of Benzyl Alcohol into Benzaldehyde |
title_full_unstemmed | Bimetallic Gold-Silver Nanoparticles Supported on Zeolitic Imidazolate Framework-8 as Highly Active Heterogenous Catalysts for Selective Oxidation of Benzyl Alcohol into Benzaldehyde |
title_short | Bimetallic Gold-Silver Nanoparticles Supported on Zeolitic Imidazolate Framework-8 as Highly Active Heterogenous Catalysts for Selective Oxidation of Benzyl Alcohol into Benzaldehyde |
title_sort | bimetallic gold-silver nanoparticles supported on zeolitic imidazolate framework-8 as highly active heterogenous catalysts for selective oxidation of benzyl alcohol into benzaldehyde |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6403852/ https://www.ncbi.nlm.nih.gov/pubmed/30961014 http://dx.doi.org/10.3390/polym10101089 |
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