Constructing asymmetric dual active sites through symbiotic effect for achieving efficient and selective photoreduction of CO to CH

One of the biggest obstacles to the light-driven conversion of greenhouse gas CO into high value-added multi-carbon compounds is manipulating the C-C coupling reaction. Herein, we propose using a symbiotic effect to construct asymmetric dual active sites, namely doping CuInS (CIS) with single atomic Ag, accompanied by the formation of sulfur vacancies (S). Thus, S and the neighbouring In metal atom double sites are constructed, and CO photoreduction products undergo a transformation from C products to CH. Meanwhile, the doped Ag plays a role in capturing and transferring photogenerated electrons, improving the reduction rate. The generation rate of CH is 53.8 μmol g h with a selectivity of 98.8%. Based on the number of transferred electrons, the catalytic activity of 2%Ag/CuInS (2%Ag/CIS) is 90 times that of CIS. Experimental and theoretical calculations verify that the key intermediates *CO and *CHO adsorbed on S and In sites, respectively, are propitious to promote the occurrence of the C-C coupling reaction owing to the reasonable distance, asymmetric electron distribution and distinct adsorption capacity. Accordingly, the findings provide a new strategy for designing asymmetric catalytic active sites for the selective photosynthesis of multi-carbon products from CO