Abstract: Photothermal catalysis technology can reduce CO₂ into chemical fuels and industrial raw materials, providing a novel green and efficient way to deal with the challenges of global warming and energy crisis. Oxygen-rich vacancy TiO₂ (TiO_2－x) photothermal catalysts was prepared by the sol-gel method combined with heat treatment in one step.The microstructure, crystal structure and optical properties were characterized by XRD, XPS, TEM and EPR.The effects of reaction conditions such as the amount of photothermal catalyst, total gas flow rate, optical density, CO₂/H₂ ratio and temperature on the photothermal reduction of CO₂ by TiO_2－x were studied, the parameters were optimized, and the photothermal catalytic mechanism of TiO_2－x was explored too.The results showed that the main product of TiO_2－x photothermal catalytic CO₂ reduction is CO.The CO yields of TiO_2－x is 2.23 mmol·g^－1·h^－1, which is 2.4 times that of commercial TiO₂ (P25).The CO yield of TiO_2－x photothermal catalysis is 59.3 times that of photocatalytic CO yield alone and 1.77 times that of thermal catalysis alone.The efficiency of photothermal synergistic catalysis is greatly improved compared to photocatalytic or thermal catalysis alone.

Key words: CO₂ reduction, photothermal catalysis, TiO₂, oxygen vacancies