The rapid elimination of volatile organic compounds and the intermediate analysis with efficient photothermal catalysis are of great significance to the environment. Oxygen vacancies (Vo) play a crucial role in structural modification and performance improvement of heterogeneous catalysts. Accordingly, here, abundant Vo sites are introduced into Co₃O₄/TiO₂ composite via treatment under H₂ and Ar flow at 200°C, and the photothermal catalytic performance of toluene is significantly improved. The molecular oxygen (O₂) adsorbed by Vo is activated to form reactive oxygen species for deep oxidation of toluene. Vo generated on the unilateral side in Co₃O₄/TiO₂ heterojunctions serves to capture electrons and break the dynamic balance of electron-hole pairs. The excited electrons are trapped by Vo, and the direct recombination of electron-hole pairs is inhibited, thus promoting the photochemical process. Moreover, the photothermal synergy effect and the relationship between Vo evolution and intermediates transformation mechanism are systematically studied.