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DOE OSTI · 1997990

Precisely doping the surface of tin-based electrocatalysts for improved CO 2 conversion to liquid chemicals

Nguyen-Phan, Thuy-Duong·Ellis, James E.·Nagarajan, Anantha Venkataraman·Howard, Bret H.·Mpourmpakis, Giannis·Kauffman, Douglas R.
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Abstract

Doping tin catalysts with sulfur can improve the electrochemical CO 2 conversion into formate/formic acid, but the lack of composition-dependent activity trends hinders further catalyst development. Here, we precisely controlled the composition of sulfur-doped Sn catalysts to show that sulfur doping only improves CO 2 conversion over a very narrow composition range, achieving maximum activity at 1.4 at% S. In situ Raman spectroscopy indicted working catalysts were in a primarily metallic state (e.g. S-Sn), and we achieved some of the highest reported partial current densities in both H-cell and full-cell electrolyzer configurations. Density Functional Theory calculations predicted S atoms preferentially occupied the catalyst surface and improved CO 2 reduction by localizing charge density at the catalyst/intermediate interface, which stabilized the *OCOH intermediate and lowered the CO 2 conversion thermodynamic barrier. Our work quantifies the composition-dependent influence of S dopants on Sn-based CO 2 reduction catalysts and provides a pathway for maximizing their CO 2 conversion activity.

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRYCO2 electrolyzerCO2 reductioncompositional dependent electrocatalysisformic acidprecise sulfur doping

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Nguyen-Phan, Thuy-Duong, Ellis, James E., Nagarajan, Anantha Venkataraman, Howard, Bret H., Mpourmpakis, Giannis, Kauffman, Douglas R.. 2023-09-01. Precisely doping the surface of tin-based electrocatalysts for improved CO 2 conversion to liquid chemicals. https://doi.org/10.1016/j.apcatb.2023.123250

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