Metal to non-metal sites of metallic sulfides switching products from CO to CH 4 for photocatalytic CO 2 reduction.

The active center for the adsorption and activation of carbon dioxide plays a vital role in the conversion and product selectivity of photocatalytic CO 2 reduction. Here, we find multiple metal sulfides CuInSnS 4 octahedral nanocrystal with exposed (1 1 1) plane for the selectively photocatalytic CO 2 reduction to methane. Still, the product is switched to carbon monoxide on the corresponding individual metal sulfides In 2 S 3 , SnS 2 , and Cu 2 S. Unlike the common metal or defects as active sites, the non-metal sulfur atom in CuInSnS 4 is revealed to be the adsorption center for responding to the selectivity of CH 4 products. The carbon atom of CO 2 adsorbed on the electron-poor sulfur atom of CuInSnS 4 is favorable for stabilizing the intermediates and thus promotes the conversion of CO 2 to CH 4 . Both the activity and selectivity of CH 4 products over the pristine CuInSnS 4 nanocrystal can be further improved by the modification of with various co-catalysts to enhance the separation of the photogenerated charge carrier. This work provides a non-metal active site to determine the conversion and selectivity of photocatalytic CO 2 reduction.