Supported Cu3 clusters on graphitic carbon nitride as an efficient catalyst for CO electroreduction to propene

Abstract

The electroreduction of carbon monoxide (COER) to multi-carbon (C₂₊) products has been emerging as a promising strategy for generating value-added fuels and chemicals, yet the development of efficient catalysts for this process still remains a huge challenge. Herein, by means of density functional theory (DFT) computations, we explored the catalytic performance of several sub-nano Cu clusters (Cu_n, n = 1–6) supported by graphitic carbon nitride (Cu_n@g-C₃N₄) for the COER. Our results revealed that the COER catalytic activities of these candidates are greatly dependent on the sizes of the anchored Cu clusters, among which Cu₃ clusters were predicted to be the best COER catalyst with a rather low limiting potential of −0.45 V for CH₄ production due to their optimal binding strength with reaction intermediates. More interestingly, at high coverage, the adsorbed CO* species can couple with each other to form a key CO–CO–CO* species via a one-step concerted trimerization mechanism with a small activation barrier of 0.43 eV, which can be further hydrogenated to propene products with a small limiting potential of −0.40 V. Thus, the anchored Cu₃ cluster on g-C₃N₄ is a quite promising catalyst for the COER with high efficiency to multi-carbon products, which offers useful guidance to further design sub-nano cluster-based catalysts for other electrochemical reactions.