Fabrication of g-C3N4/TiO2 heterojunction composite for enhanced photocatalytic hydrogen production

Abstract In this study, graphitic carbon nitride (g-C3N4) was successfully coupled with TiO2 using hydrothermal method, to develop an advanced heterojunction photocatalyst. The interaction between g-C3N4 and TiO2 was confirmed through analysis of X-Ray spectroscopy (XPS) C 1s, N 1s, O 1s high resolution core level spectra of g-C3N4, TiO2 and g–C3N4–TiO2 heterojucntion. Further, through valence band spectra analysis, conduction band offset (0.12 eV) and valence band offset (0.28 eV) of g–C3N4–TiO2 heterojunction were estimated. Also, composite material was identified as type II heterojunction between g-C3N4 and TiO2. XRD, UV–vis, BET and HRTEM were employed to understand the changes in physicochemical properties. Photocatalytic hydrogen production rates were evaluated through water splitting experiments. Under visible light irradiation highest hydrogen production rate was achieved for g–C3N4–TiO2 heterojunction sample with high content of TiO2, and was about 1041 μmol/g.h. The improved photocatalytic activity of the heterojunction material was explained in detail.