Tuning Crystallinity and Surface Hydrophobicity of a Cobalt Phosphide Cocatalyst to Boost CO2 Photoreduction Performance

Photocatalytic CO2 conversion is a promising method to yield carbon fuels, but it remains challenging to regulate catalytic materials for enhanced reaction efficiency and tunable product selectivity. This study concerns the development of a facile and efficient thermal post‐treatment method to improve the crystallinity and surface hydrophobicity of a cobalt phosphide (CoP) cocatalyst, which promotes the separation and transfer of photoexcited charge carriers, reinforces CO2 chemisorption, and weakens the H2O affinity. Compared with pristine CoP, the optimal CoP‐600 cocatalyst displays a 3.5‐fold enhancement in activity and a 2.3‐fold increase in selectivity for the reduction of CO2 to CO with a high rate of 68.1 μmol h−1.