Static Internal Electric Field in Heterojunctions Composed of O-C3N4 Nanosheets Decorated with NH2-MIL-101(Cr) Nanoparticles for Photocatalytic Hydrogen Evolution

Photocatalytic water decomposition is a cost-effective way to convert sustainable solar energy into chemical energy. While semiconductor photocatalysis has generated considerable interest in photocatalytic hydrogen evolution, it is hampered by fast electron-hole complexation and suboptimal efficiency. Herein, an NH2-MIL-101(Cr)/doped-C3N4 heterojunction possessing a static internal electric field (IEF) is successfully prepared, characterized, and assessed for photocatalytic hydrogen production. The optimized photocatalytic H-2 evolution rate of the resultant NH2-MIL-101(Cr)/O-C3N4 is 460 mu mol g(-1) h(-1) under visible light, with an AQY of 2.5% at 450 nm. Spectral evidence indicates that the static IEF facilitates rapid electron transfer from NH2-MIL-101(Cr) to O-C3N4, achieving efficient photogenerated charge separation and a consequent significant enhancement in catalytic activity. This work not only presents a case of construction of an IEF through assembling NH2-MIL-101(Cr) with O-C3N4 but also deepens the insight of the rudimentary mechanisms of the static IEF in heterojunctions for photocatalytic hydrogen evolution.