The enhanced photo-catalytic CO2 reduction performance of g-C3N4 with high selectivity by coupling CoNiSx

Abstract In photo-catalysis, noble metals generally serve as co-catalysts, while the rarity limited their practical applications. In this case, transition metal sulfide was proved to potential substitute for noble metals owing to their peculiar photo-electrochemical properties. Here, bimetallic CoNiSx was coupled with g-C3N4 to form composite and played as a role of co-catalyst to improve the photo-catalytic activity. Notably, compared with pristine g-C3N4, the CoNiSx-CN composite exhibits superior photo-catalytic CO2 reduction activity and manifests high selectivity to CO production. The production rate of CH4 and CO in this reaction can reach 0.904 and 11.77 μmol‧ g−1 h−1, correspondingly, where the CO yield is nearly 10-fold comparable to solely g-C3N4. The excellent performance of composite can be attributed to the enhanced charge separation, light absorption ability and photo-thermal effect with the existence of CoNiSx. This study shed light on the enhancement of photo-catalytic CO2 reduction based on bimetallic co-catalyst loaded on g-C3N4.