Abstract
The stability of supported metal particles is an important parameter in heterogenous catalysis. For silver catalysts supported on α-alumina, industrially used in ethylene epoxidation, the loss of silver surface area as result of particle growth is one of the most important deactivation mechanisms. In this work, the growth of silver particles was investigated by exposing catalysts to thermal treatments. The presence of oxygen during heating strongly enhanced particle growth, and the interparticle distance was a crucial parameter. However, restricting movement of complete silver particles using cage-like α-alumina did not limit particle growth. These findings indicate that Ostwald ripening was the dominant mechanism behind particle growth, with the diffusion of oxidized silver species being a rate limiting factor. Finally, higher surface area α-alumina provided better silver stability during ethylene epoxidation, with only limited decrease in selectivity. This makes silver supported on high surface area α-alumina promising candidates for ethylene epoxidation catalysis.
Original language | English |
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Pages (from-to) | 534-544 |
Number of pages | 11 |
Journal | Journal of Catalysis |
Volume | 405 |
DOIs | |
Publication status | Published - Jan 2022 |
Bibliographical note
Funding Information:This research was funded by the Netherlands Center for Multiscale Catalytic Energy Conversion (MCEC), an NWO Gravitation programme funded by the Ministry of Education, Culture and Science of the government of the Netherlands and by an NWO-Vici grant (16.130.344). The authors would like to thank Eric Helleband (SEM), Hans Meeldijk (SEM), Remco Dalebout (N2-physisorption), Yuang Piao (NH3-TPD), Johan de Boed (UV/Vis, catalytic setup) and Jan Willem de Rijk (catalytic setup) for technical support.
Funding Information:
This research was funded by the Netherlands Center for Multiscale Catalytic Energy Conversion (MCEC) , an NWO Gravitation programme funded by the Ministry of Education, Culture and Science of the government of the Netherlands and by an NWO-Vici grant ( 16.130.344 ). The authors would like to thank Eric Helleband (SEM), Hans Meeldijk (SEM), Remco Dalebout (N 2 -physisorption), Yuang Piao (NH 3 -TPD), Johan de Boed (UV/Vis, catalytic setup) and Jan Willem de Rijk (catalytic setup) for technical support.
Publisher Copyright:
© 2021 The Authors
Funding
This research was funded by the Netherlands Center for Multiscale Catalytic Energy Conversion (MCEC), an NWO Gravitation programme funded by the Ministry of Education, Culture and Science of the government of the Netherlands and by an NWO-Vici grant (16.130.344). The authors would like to thank Eric Helleband (SEM), Hans Meeldijk (SEM), Remco Dalebout (N2-physisorption), Yuang Piao (NH3-TPD), Johan de Boed (UV/Vis, catalytic setup) and Jan Willem de Rijk (catalytic setup) for technical support. This research was funded by the Netherlands Center for Multiscale Catalytic Energy Conversion (MCEC) , an NWO Gravitation programme funded by the Ministry of Education, Culture and Science of the government of the Netherlands and by an NWO-Vici grant ( 16.130.344 ). The authors would like to thank Eric Helleband (SEM), Hans Meeldijk (SEM), Remco Dalebout (N 2 -physisorption), Yuang Piao (NH 3 -TPD), Johan de Boed (UV/Vis, catalytic setup) and Jan Willem de Rijk (catalytic setup) for technical support.
Keywords
- Ethylene epoxidation
- High surface area
- Macroporous α-alumina
- Ostwald ripening
- Silver
- Stability