To mitigate the excess atmospheric CO2 sustainably, one promising way is CO2 electroreduction reaction into valuable C2 products (CO2RR-to-C2) such as ethanol and ethylene using renewable electricity. Cu is the most ideal pure metal catalyst for CO2RR-to-C2 but suffers from high overpotentials and low selectivity of C2 species To reduce the overpotentials and enhance the selectivity of CO2RR-to-C2 over Cu, we designed a hybrid organic inorganic interface between aminothiolate self-assembled monolayer (SAM) and Cu catalyst.1,2 We studied the electrocatalytic performance of CO2RR-to-C2 via varying the carbon chain lengths and surface coverages of aminothiolate SAMs. Our results (Figure 1) show that: (1) aminothiolate SAMs prefer flat-lying over the Cu surface at low coverage, while it favors upright over the surface at high coverage due to the lateral interactions; (2) the aminothiolate SAM with longer carbon chain lengths is more stable under electrochemical conditions; (3) Cu surface reconstruction is suppressed with the aid of strong-bound SAMs; and (4) the rate-determining steps of CO2 activation (COOH* formation) and the selectivity of C2 products (C-C coupling) are promoted by the induced hydrogen bond effect and dual-active sites (i.e., organic nitrogen site and inorganic copper site). Overall, this theoretical research provides an innovative picture of electrocatalysis at hybrid organic-inorganic interfaces, and specifically their roles in increasing the catalytic activity and selectivity.

Self-assembled monolayer: Metal interfaces driven CO2 capture and conversion

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