An effective strategy to improve the photothermocatalytic activity of Co3O4 for VOCs degradation: Specifically enhancing the surface lattice oxygen activity

Co3O4 catalysts with active surface lattice oxygen were constructed via a simple solvothermal method by adopting isopropyl alcohol (IPA) or tert-butyl alcohol (TBA) as solvent. The obtained Co3O4-IPA and Co3O4-TBA exhibit flower-like structures with (1 1 2) planes exposed on the surface. Due to abundant unsaturated Co3+ sites existing on the (1 1 2) plane, the content and activity of surface lattice oxygen on Co3O4-IPA and Co3O4-TBA are much higher than that on Co3O4-MA and Co3O4-EA, which prepared with methyl alcohol or ethyl alcohol as a solvent. The robust surface lattice oxygen on Co3O4-IPA and Co3O4-TBA facilitates the ring-opening process during photothermocatalytic oxidation of toluene, significantly promoting the catalytic performance. In the static atmosphere, about 98% of toluene conversion and 80% of CO2 yield can be achieved on Co3O4-IPA and Co3O4-TBA under full-spectrum light irradiation of 325 mW/cm2, much higher than 89% and 73% of conversion, 50% and 26% of CO2 yield on Co3O4-EA and Co3O4-MA, respectively.