Porous carbon nitride with defect mediated interfacial oxidation for improving visible light photocatalytic hydrogen evolution

Abstract

The Feasibility of interfacial redox reaction has determinant role in hydrogen evolution during photocatalytic water-splitting process. Here, we report that promoting interfacial oxidation ability of porous graphitic carbon nitride (Pg-C3N4) with defects can effectively improve visible light photocatalytic hydrogen evolution (PHE) activity. Pg-C3N4 with edge site defects was fabricated by constraining growth of g-C3N4 on porous kaolinite-derived template. The Pg-C3N4 with extra electrons of defects caused by enriched basal plane holes exhibits higher electrocatalytic activity for oxidation process in comparison with reduction process. This feature benefits electron-transfer reaction to quench photo-excited holes during photocatalysis process and promote photoelectrons reaction, which was proved by photoluminescence spectra of Pg-C3N4 and g-C3N4 and different PHE activity variation of their heterojunction materials with TiO2. The results show that PHE rate for Pg-C3N4 reaches 1917 umol−1 g−1 h−1, 2.37 times of g-C3N4 under visible light irradiation. This approach of engineering interfacial defects to accelerate hole’s oxidation reactions during photocatalytic water-splitting would advance two-dimensional (2D) catalysis for solar fuel production.