Amorphous-crystalline junction oxygen vacancy-enriched CoPi/ZnIn2S4/a-B-TiO2 catalyst for oxygen evolution reaction

•A new strategy was applied to synthesize TiO2 with B doping and amorphous-crystalline junction, and it was proved by experiments that it contained a large number of oxygen vacancies.•B doping mainly improves the conduction band structure, while the amorphous-crystalline junction acts on the valence band. The synergistic effect regulated the bandgap, promoted the deviation of the internal electric field, and improves the PEC efficiency.•The a-B-TiO2 homojunction, ZnIn2S4/a-B-TiO2 heterojunction and kinetic modification are cooperatively coupled to further improve PEC efficiency.