Study on the Effect and Mechanism of Hydrothermal Modification on TiO2 Catalysts for CO2 Photo-Thermal Reduction.

Photocatalysts like TiO₂ can harness sunlight to reduce CO₂ into valuable hydrocarbon fuels, representing a promising solution for carbon neutrality and sustainable energy challenges. Herein, the effect of hydrothermal modification on the CO₂ photothermal reduction activity of TiO₂ catalyst was studied, through photo-catalytic performance test, XRD, Raman, N₂ adsorption, SEM, TEM, CO₂-TPD, UV-vis DRS, and PL on commercial and modified TiO₂. The results show that the hydrothermal-modified TiO₂-NBS is a pure anatase phase, which has a narrower band gap than the mixed anatase and rutile structure of commercial TiO₂-P25, and is more favorable to the excitation of photon-generated carriers. Meanwhile, the light emission intensity of anatase phase is weaker, which is conducive to electron-hole separation, promoting the reactant intermediate conversion. In addition, compared with TiO₂-P25, TiO₂-NBS has better morphology and specific surface pore characteristics, more adsorption sites for CO₂, and stronger adsorption strength, which facilitate the adsorption and activation reactions of CO₂. As a result, TiO₂-NBS exhibits stronger CO₂ photothermal reduction activity, with CO and CH₄ production rates of 6.49 µmol g⁻¹ h⁻¹ and 1.56 µmol g⁻¹ h⁻¹, which are 2.58 times and 2.84 times those of TiO₂-P25, respectively. [ABSTRACT FROM AUTHOR]