Theoretical Prediction and Synthesis of Nonmetal-Doped Anatase TiO2 (101) for Boosting Photocatalytic Hydrogen Evolution Reaction

TiO2-based photocatalysts are eco-friendly, cost-effective, and stable but only exert catalytic performance in the ultraviolet region, and the photocatalytic efficiency is very low. In this work, we employ DFT calculations to deeply investigate the effect of nonmetallic C-doped TiO2 (101) on the photocatalytic hydrogen evolution performance. Specifically, the effects of C substitution or interstitial doping at the surface, subsurface, and bulk on the electronic structure, optical properties, and catalytic hydrogen evolution activity were substantially investigated. We discovered that different C atom doping strategies impinge different effects on the catalytic activity. Among them, the CO-bulk4, CTi-surf2, and Cinter-surf systems showed superior catalytic activities with ΔG of −0.012, −0.055, and −0.024 eV, respectively. The C atom replaces the Ti atom and alters the original coordination environment, which leads to charge redistribution and consequently to the activation of the O sites. Additionally, carbon-self-doped TiO2 photocatalysts were fabricated using an experimental hydrothermal synthesis, and the XPS analyses confirmed that O is replaced by C. In addition, the photocatalytic hydrogen evolution rate is 0.3 mmol g–1 h–1, while there is no hydrogen evolution for pure TiO2. Our findings suggest that nonmetallic doped TiO2(101) photocatalysts can improve light absorption, modulate charge distribution, and enhance hydrogen evolution activity.