Transition of Schottky to Ohmic Contact via P Doping Promotes Efficient H₂ Evolution of g-C₃N₄

Abstract

Utilizing photocatalysis to split water is a highly prospective technique for H2 evolution. However, carrier recombination in photocatalysts results in poor photocatalytic H2 evolution performance. The introduction of metallic substances as cocatalysts has found extensive application in enhancing photocatalytic performance. However, the existence of Schottky barriers remains a hindrance to the separation of photogenerated carriers. In this work, the electronic structure of g-C3N4 was modulated and optimized by P doping, changing the contact mode from the Schottky contact to the Ohmic contact, greatly promoting photogenerated charge separation and transfer. Under xenon lamp illumination, the H2 production rate of the prepared Ohmic contact photocatalyst is nearly 5 times that of the original Schottky contact one. This work gives new insights into the rational design of an efficient water-splitting photocatalyst.