Steering the Product Selectivity of CO2 Electroreduction by Single Atom Switching in Isostructural Copper Nanocluster Catalysts.

Even single atom manipulation can cause drastically changes in catalytic activity and selectivity, especially in atomic-level catalysts. However, it is challenging to accurately elucidate the influence of specific atom on performance due to the intertwined factors in catalysts. Atomically precise isostructural nanoclusters (NCs) can serve as ideal platforms to uncover the impact of individual atom on catalytic property. Herein, a pair of isostructural Cu NCs ([Cu13(SC6H3F2)3(P(PhF)3)7H10]0 and [Cu14(SC6H3F2)3(P(PhF)3)8H10]+ namely as Cu13 and Cu14) were synthesized. In electrochemical CO2 reduction reaction, Cu13 shows barely activity towards only 2e product CO with maximum 13% FE at -1.1 V. In contrast, Cu14 can promote CO2 deep reduction to hydrocarbons (CH4 and C2H4) with maximum FE of 54.3% at -1.2 V. Based on the crystallographic and computational analyses, the extra Cu at the top in Cu14 squeezes the H connected with three core Cu into the center of the same plane, optimizing the electronic structure and thereby promoting CO2 activation and H2O dissociation, which is further confirmed by comprehensive in situ characterizations, kinetic experiments, and theoretical calculations. This work provides a unique isostructural NCs system to gain fundamental insights into switching catalytic reactivity by single atom manipulation.