The Promoted Photocatalytic Mechanism of N-Doped Graphene /Tio2 Composites : From Experiment to Theory

Degradation of unsymmetrical dimethylhydrazine (UDMH) by graphene-based semiconductor composites is an effective photocatalytic method. To make full use of the solar energy, the composites were doped by non-metal atoms in the recent research. One critical issue for the composites is understanding the electronic property relating to light absorption and carrier transfer. In this study, the NG (N-doped graphene) /TiO2 composites were fabricated, characterized and deeply investigated based on the density functional theory (DFT) calculation. Particularly, the resultant new energy levels in the band structure could decrease the bandgap of semiconductor, promote charge-transfer at the interface of graphene and TiO2, improve the light absorption, and finally enhance the photocatalytic activities. An excellent agreement of electron properties is found between our theoretical calculations and the characterization analysis of UV-vis DRS and RAMAN spectra. A possible photocatalytic mechanism based on the band structure and ESR result was developed. Thus, the NG/TiO2 composite could be a promising photocatalyst for UDMH degradation under the visible light