Revealing the synergistic effect of bulk and surface co-doped boron on TiO2 for enhanced photocatalytic H2 evolution

Boron(B) doping is considered as a promising modification method for TiO2 photocatalyst due to the facilitation of separation and migration of photogenerated carriers. However, the modification mechanisms of bulk or surface doping modes on photocatalyst are controversial, and the catalytic activity still needs to be improved. Here, a bulk and surface B co-doped TiO2 (B(B&S)-TiO2) derived from B-containing Ti-MOF (MIL-125(B)) precursor was demonstrated, which achieved a H2 evolution rate of 9.56 mmol∙g−1∙h−1 under 365 nm light without co-catalyst. Detailed investigations reveal the synergistic effect between bulk and surface co-doped B, which optimizes the microstructure, activates the 3-coordinated O (O3C) atoms of B-Ti-O structural units as active sites, enhances the transfer of photoelectrons and inhibits the recombination, balances H* adsorption–desorption during the photocatalytic reactions. This work exhibits a novel strategy of bulk and surface B co-doped photocatalysts and highlights the potential for achieving high photocatalytic H2 evolution rate without co-catalyst.