Unraveling the Polarization Effect on P-Doped NiO Nanosheets for Efficient Photocatalytic CO ₂ Reduction

Sluggish charge transfer and a high surface reaction barrier are bottleneck problems of photocatalytic CO2 reduction. The search for strategies that can accelerate charge dynamics and lower the surface reaction barrier synchronously remains challenging. Here, we put forward a surface polarization strategy to promote photocatalytic CO2 reduction over NiO nanosheets by phosphorus (P) elemental doping. The as-prepared P-doped NiO nanosheets (P–NiO) exhibit superior photocatalytic CO2-to-syngas conversion performance with tunable ratios of CO/H2 when accepting photogenerated electrons from both [Ru(bpy)3]Cl2 and CdSe/S colloidal crystal light absorbers. It is revealed that doping P in NiO nanosheets can modulate the polarization to promote the transfer of photoexcited electron–hole pairs and also upshift the d-band center of the Ni active site for facilitating the adsorption of reactant and lowering the activation energy barriers of both the *COOH and H* intermediates, thus promoting the photocatalytic CO2-to-syngas conversion reaction.