Photothermocatalytic Removal of CO and Formaldehyde with Excellent Water Vapor Stability over Dual-Functional Copper Loading on TiO2 Synthesized via Flame Spray Pyrolysis

Photothermocatalytic (PTC) oxidation is a high-efficient, low-temperature, and green approach to eliminate the air pollutant, but its application is drastically restricted by lack of low-cost, active, and superior water-resistance catalysts. Herein, the influence of bifunctional copper components on TiO2 is experimentally and theoretically investigated to optimize PTC efficiency for the CO and HCHO oxidation via flame spray pyrolysis. Both the abundant lattice doping and highly dispersed nanocluster modification of hybrid CuOx remarkably enhance charge separation, maintain a dynamic Cu+/Cu2+ balance, and decrease oxygen vacancy formation energy. The satisfactory PTC CO and HCHO oxidation on the CuOx-TiO2 samples is mainly attributed to higher lattice oxygen activity and less reaction intermediates under irradiation. In addition, the essential synthesis parameters, such as the increasing precursor flux, are assessed to further enhance the PTC performance. Interestingly, photocatalysis effectively removes the surface H2O or hydroxyl group of catalysts, which is responsible for the excellent water vapor stability in the lean CO PTC oxidation.

Automated summary

The study demonstrates that the influence of hybrid CuOx components on TiO2 can enhance the efficiency of photothermocatalytic oxidation reactions, mainly due to higher lattice oxygen activity and reduced oxygen vacancy formation energy. Additionally, essential synthesis parameters such as precursor flux are evaluated to further improve the performance of photothermocatalytic oxidation.