Enhancement of visible light photocatalytic hydrogen evolution by bio-mimetic C-doped graphitic carbon nitride

Abstract

Abstract Bio-mimetic C-doped graphitic carbon nitride (g-C3N4) with mesoporous microtubular structure has been prepared by a simple chemical wet bio-template impregnation approach (direct impregnation and hydrothermal impregnation) using urea as a precursor and kapok fibre as bio-template and in-situ carbon dopant. Our finding indicated that the hydrothermal impregnation had induced more in-situ C-doping in g-C3N4 as compared to the direct impregnation approach. The introduction of in-situ C doping in the g-C3N4 and the mesoporous microtubular structure remarkably enhanced light-harvesting capability up to near infrared regions. The photocurrent measurement and electrochemical impedance spectroscopy (EIS) analysis suggested that the bio-template C-doped g-C3N4 exhibits a superior photoinduced electron-hole pairs separation efficiency due to C doping and mesoporous microtubular structure significantly promotes excellent conductivity and electron redistribution in the sample. C-doped graphitic carbon nitride sample prepared by the hydrothermal (HB/g-C3N4) approach exhibits excellent photocatalytic hydrogen production with an H2 production rate of 216.8 μmol h−1 g−1 which was a 1.3 and 2.9 improvement over C-doped graphitic carbon nitride prepared by direct impregnation (DB/g-C3N4) and pristine g-C3N4, respectively. This study provides new insights into the development of low-cost and sustainable photocatalysts for photocatalytic hydrogen production.