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

Abstract Photocatalytic CO 2 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 CO 2 chemisorption, and weakens the H 2 O 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 CO 2 to CO with a high rate of 68.1 μmol h −1 .