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Nano-Folded Gold Electrocatalysts Enhance the Selectivity of Carbon Dioxide Reduction

preprint
submitted on 19.06.2019 and posted on 20.06.2019 by Kam Sang Kwok, Yuxuan Wang, Michael Cao, Hao Shen, Weinan Xu, David Muller, Chao Wang, David Gracias

The local structure and geometry of catalytic interfaces can influence the selectivity of chemical reactions. Here, using a pre-strained polymer, we uniaxially compress a thin gold film to form a nano-folded catalyst. We observe two kinds of folds and can tune the ratio of loose to tight folds by varying the extent of pre-strain in the polymer. We characterize the nano-folded catalysts using x-ray diffraction, scanning, and transmission electron microscopy. We observe grain reorientation and coarsening in the nano-folded gold catalysts. Electroreduction of carbon dioxide with these nano-folded catalysts reveals an enhancement of Faradaic efficiency for carbon monoxide formation by a factor of about four. This result suggests that electrolyte mass transport limitations and an increase of the local pH in the tight folds of the catalyst outweigh the effects of alterations in grain characteristics. Together, our studies demonstrate that nano-folded geometries can significantly alter grain characteristics, mass transport, and catalytic selectivity.

Funding

Air Force Office of Scientific Research MURI program (FA9550-16-1-0031), and the National Science Foundation (CMMI-1635443).

History

Email Address of Submitting Author

dgracias@jhu.edu

Institution

Johns Hopkins University

Country

USA

ORCID For Submitting Author

0000-0003-2735-4725

Declaration of Conflict of Interest

N/A

Exports