Construction of Asymmetric Phosphorus–Cobalt Dual Sites for Effectively Reducing CO2 to CO

With increasing global energy demand and growing concerns over climate change, methods for catalytic reduction of CO 2 have been extensively studied, among which graphitic carbon nitride (g-C 3 N 4 ) attracts remarkable attention due to its easily available raw materials and outstanding chemical stability. However, its wide bandgap and low photon usage efficiency limit its application in photocatalysis. Doping g-C 3 N 4 to introduce active sites can enhance its catalytic performance. Herein, asymmetric phosphorus–cobalt dual sites were introduced onto g-C 3 N 4 via hydrothermal treatment and thermal polymerization. P (phosphorus) could enhance CO 2 adsorption, while Co (cobalt) functions as a metallic site to boost the separation rate of photogenerated carriers. A photocatalytic CO 2 reduction to CO with a rate of 93.2 μmol/(g·h) was achieved, which was two times that of g-C 3 N 4 . During stability testing, ethylene with a formation rate of approximately 2 μmol/(g·h) was observed, as well as trace quantities of methanol and acetic acid in the liquid products. This work shows a promising strategy by the introduction of asymmetric phosphorous–cobalt dual sites for efficient photocatalytic conversion of CO 2 to CO and C2 products.