2D Z-scheme heterojunction and oxygen deficiency synergistically boosting the photocatalytic activity of a layered BaTiO3/BiOIO3 composite

•A layered BaTiO3/BiOIO3 composite was constructed via a versatile hydrothermal method.•The BaTiO3/BiOIO3 composite exhibited an outstanding photo response, separation efficiency and high redox capability of photo-excited carriers due to the synergistic effect of rich oxygen deficiency and 2D Z-scheme heterojunction with IO3−/I− redox pairs.•The IO3−/I− redox pair and coupled band gap of the BaTiO3/BiOIO3 composite were highly related to oxygen deficiency.•The BaTiO3/BiOIO3 composite performed an ultrahigh catalytic activity toward to the photo-degradation of tetracycline and rhodamine B.