Highly Selective and Efficient Solar‐Light‐Driven CO2 Conversion with an Ambient‐Stable 2D/2D Co2P@BP/g‐C3N4 Heterojunction

Renewable solar‐driven carbon dioxide (CO2) conversion to highly valuable fuels is an economical and prospective strategy for both the energy crisis and ecological environment disorder. However, the selectivity and activity of current photocatalysts have great room for improvement due to the diversification and complexity of products. Here, an ambient‐stable 2D/2D Co2P@BP/g‐C3N4 heterojunction is designed for highly selective and efficient photocatalytic CO2 reduction reaction. The resulting Co2P@BP/g‐C3N4 material has a remarkable conversion of CO2 to carbon monoxide (CO) with an ≈96% selectivity, coupled with a dramatically increased CO generation rate of 16.21 µmol g–1 h–1, which is 5.4 times higher than pristine graphitic carbon nitride (g‐C3N4). In addition, this photocatalyst exhibits good ambient stability of black phosphorus (BP) without oxidation even over 180 days. The excellent photocatalytic selectivity and activity of Co2P@BP/g‐C3N4 heterojunction are attributed to its lower energy barriers of *COOH, *CO, and *+CO in the process of CO2 reduction, coupled with rapid charge transfer at the heterointerfaces of BP/g‐C3N4 and Co2P/BP. This is solidly verified by both density functional theory calculation and mechanism experiments. Therefore, this work holds great promise for an ambient‐stable efficient and high selectivity photocatalyst in solar‐driven CO2 conversion. An ambient‐stable 2D/2D Co2P@BP/g‐C3N4 heterojunction is manufactured for highly selective and efficient photocatalytic CO2 conversion. Carbon monoxide is almost directionally generated with a selectivity of 96% and yield of 16.21 µmol g–1 h–1. Density functional theory calculation illustrates the above results by the Gibbs free energies of *COOH, *CO, *HCO, and *+CO.