Ternary red phosphorus/CoP2/SiO2 microsphere boosts visible-light-driven photocatalytic hydrogen evolution from pure water splitting

Red phosphorus (RP) is a promising visible-light-driven semiconductor for photocatalytic hydrogen evolution, but the activity is restricted due to the rapid charge carrier recombination and sluggish surface reaction kinetics. Herein, cobalt phosphide (CoP2) modified RP heterostructure was developed by in situ phosphorization of cobalt oxide from phosphorus vapor. By tuning the amounts of CoP2 in the heterostructure, the optimized hybrid exhibited a HER rate reaching 11.79 μmol h−1 under visible light illumination, which is 3.5 times higher than that of the RP with Pt as cocatalyst. It was experimentally indicated that the intimate interaction between CoP2 and RP gave rise to improved visible light absorption and accelerated photogenerated electron–holes separation. Moreover, the CoP2 as a noble-metal-free cocatalyst could promote the surface hydrogen evolution reaction, which synergetic benefited the photocatalytic hydrogen production activity.