Abstract:
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The electrochemical reduction of atmospheric CO2 by renewable
electricity opens new routes to synthesize fuels and chemicals, but more selective and
efficient catalysts are needed. Herein, by combining experimental and first-principles
studies, we explain why chalcogen modified copper catalysts are selective toward formate
as the only carbon product. On the unmodified copper, adsorbed CO2 is the key
intermediate, yielding carbon monoxide and formate as carbon products. On sulfur,
selenium, or tellurium modified copper, chalcogen adatoms are present on the surface and
actively participate in the reaction, either by transferring a hydride or by tethering CO2
thus suppressing the formation of CO. These results highlight the active role of chalcogen
centers via chemical steps and point toward basicity as the key descriptor for the stability
and selectivity of these catalysts. |