Construction of CoP/Cu3P/Ni2P Double S-Scheme Heterojunctions for Improved Photocatalytic Hydrogen Evolution

The S-scheme heterojunctions exhibit great potential for photocatalytic hydrogen evolution, which helps not only maintain a stronger redox capability for photocatalysts but also achieve the efficient separation and transfer of photo-induced charge carriers. Herein, metal-organic frameworks (MOF)-derived CoP/Cu3P/Ni2P (CCNP) double S-scheme photocatalytic systems were constructed by simple hydrothermal and phosphating. The optimized CCNP photocatalyst revealed the maximum photocatalytic hydrogen evolution activity of 786.58 μmol with an apparent quantum efficiency of 3.69%, which is roughly 2.64 and 3.33 times higher than that of CoP (CP) and CoP/Ni2P (CNP), respectively. The improved hydrogen production performance is attributed to the formation of S-scheme heterojunctions that facilitate the accelerated electron–hole transfer while maintaining the strong redox ability of the catalysts, and to the fact that the MOF-derived composite catalysts still maintain the dodecahedral shape that facilitates the attachment of Cu3P and Ni2P, while their tight bonding facilitates the charge transfer. This work helped design a novel double S-scheme CoP/Cu3P/Ni2P heterojunction derived from MOF for efficient artificial solar energy conversion.