ZIF-67-Derived Co₃O₄ with Dynamic Active Sites Enabling SrTiO₃ for Efficient Photocatalytic Overall Water Splitting

Developing efficient and stable non-noble metal cocatalysts represents a promising yet challenging frontier in the field of photocatalytic water splitting. Herein, ZIF-67 derived Co3O4 nitrogen doped graphitic carbon (Co3O4 NGC) is uniformly deposited onto the surface of Al-doped SrTiO3 (STO) via an in situ growth combined with a heat treatment method. The prepared Co3O4 NGC/STO exhibits excellent activity for photocatalytic overall water splitting with stoichiometric H2 and O2 evolution, and the highest H2 evolution rate reaches 1099 μmol h–1 g–1 with an apparent quantum yield of 9.27% at 365 nm, which is even higher than that of Pt loaded STO. In situ X-ray photoelectron spectroscopy accompanied by comprehensive characterizations demonstrate that the photogenerated electrons and holes respectively accumulate at Co3O4 NGC and STO as driven by interfacial electric field, and Co3O4 NGC containing Co3+/Co2+ redox couples acts as dynamic active sites to significantly reduce the energy barrier for water splitting.