Steam-created grain boundaries for methane CÐH activation in palladium catalysts.
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| Title: | Steam-created grain boundaries for methane CÐH activation in palladium catalysts. |
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| Authors: | Huang, Weixin, Johnston-Peck, Aaron C., Wolter, Trenton, Yang, Wei-Chang D., Xu, Lang, Oh, Jinwon, Reeves, Benjamin A., Zhou, Chengshuang, Holtz, Megan E., Herzing, Andrew A., Lindenberg, Aaron M., Mavrikakis, Manos, Cargnello, Matteo |
| Source: | Science (pre-March 2025). 9/24/2021, Vol. 373 Issue 6562, p1518-1523. 6p. 4 Diagrams. |
| Subjects: | Palladium catalysts, Crystal grain boundaries, Carbon-hydrogen bonds, Metal nanoparticles, Catalytic activity, Hydrogen evolution reactions |
| Abstract: | Defects may display high reactivity because the specific arrangement of atoms differs from crystalline surfaces. We demonstrate that high-temperature steam pretreatment of palladium catalysts provides a 12-fold increase in the mass-specific reaction rate for carbon-hydrogen (C–H) activation in methane oxidation compared with conventional pretreatments. Through a combination of experimental and theoretical methods, we demonstrate that an increase in the grain boundary density through crystal twinning is achieved during the steam pretreatment and oxidation and is responsible for the increased reactivity. The grain boundaries are highly stable during reaction and show specific rates at least two orders of magnitude higher than other sites on the palladium on alumina (Pd/Al2O3) catalysts. Theoretical calculations show that strain introduced by the defective structure can enhance C–H bond activation. Introduction of grain boundaries through laser ablation led to further rate increases. [ABSTRACT FROM AUTHOR] |
| Copyright of Science (pre-March 2025) is the property of American Association for the Advancement of Science and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Psychology and Behavioral Sciences Collection |
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| Abstract: | Defects may display high reactivity because the specific arrangement of atoms differs from crystalline surfaces. We demonstrate that high-temperature steam pretreatment of palladium catalysts provides a 12-fold increase in the mass-specific reaction rate for carbon-hydrogen (C–H) activation in methane oxidation compared with conventional pretreatments. Through a combination of experimental and theoretical methods, we demonstrate that an increase in the grain boundary density through crystal twinning is achieved during the steam pretreatment and oxidation and is responsible for the increased reactivity. The grain boundaries are highly stable during reaction and show specific rates at least two orders of magnitude higher than other sites on the palladium on alumina (Pd/Al2O3) catalysts. Theoretical calculations show that strain introduced by the defective structure can enhance C–H bond activation. Introduction of grain boundaries through laser ablation led to further rate increases. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 00368075 |
| DOI: | 10.1126/science.abj5291 |
