Enhanced photocatalytic hydrogen evolution and CO2 to CH4 selectivity of Co3O4/Ti3+-TiO2 hollow S-scheme heterojunction via ZIF-67 self-template and Ti3+/Ov

The potential would be an important issue for enhancing photocatalytic HER and CO2 photoreduction selectivity. Herein, the Co3O4/Ti3+-TiO2 hollow S-scheme heterojunction is fabricated via continuous light modification-chemical-annealing-reduction method. Eval-uated by photocatalytic performance, the as-prepared Co3O4/Ti3+-TiO2 hollow S-scheme heterojunction exhibits remarkable photocatalytic performance enhancement than single TiO2, including hydrogen evolution (-396.16 mmol/g center dot h,-15 folds) and CO2 photoreduction (H2/CH4/CO:-20.32/80.57/9.85 mmol/g center dot h,-20 folds), and achieves CO2 photoreduction to CH4 selectivity enhancement, which can be mainly ascribed to the synergism of Ti3+/Ov and S-scheme heterojunction. There, Ti3+/Ov can not only increase the solar efficiency, but also decrease the energy barrier of H+ and *CO photoreduction to enhance HER and CO2 to CH4 selectivity, including promote the H+ diffusion and CO2 absorption. Additionally, the formed Co3O4/Ti3+-TiO2 S-scheme heterojunction can promote the photo-generated carrier