Photothermal synergistic catalytic oxidation of ethyl acetate over MOFs-derived mesoporous N-TiO2 supported Pd catalysts

Abstract

To overcome the main challenge of low photocatalytic efficiency and high energy consumption of thermocatalysis in the oxidation of volatile organic compounds (VOCs), MOF-derived mesoporous disk-like yPd/xN-TiO2 (x = 3.2, 5.5, 7.7 wt%, and y = 0.26 wt%) were prepared by ball milling-calcination method for photothermal catalytic oxidation of ethyl acetate. Morphological and pore structure characterization indicated that Pd/N-TiO2 had abundant pore structure and large specific surface area, which facilitated the adsorption of pollutants on the active sites. Among the catalysts, 0.26 Pd/3.2 N-TiO2 exhibited optimal photothermal catalytic performance. The corresponding temperature required for 50% and 90% conversion of ethyl acetate was 192 and 212 °C, with the specific reaction rate of 0.95 µmol/(gPd s) at 150 °C. Doping of N and loading of Pd nanoparticles enhanced the light absorption capacity, promoted the charge separation, and the adsorption capacity of ethyl acetate, resulting in a high photothermal catalytic oxidation activity. The detection of free radicals indicated that the photothermal synergy was associated with the generation of reactive oxygen species over 0.26 Pd/3.2 N-TiO2 under light irradiation condition, which directly participated in the catalytic removal of ethyl acetate. A proper increase in temperature could also promote the migration of carriers. The photothermal catalytic oxidation of VOCs over MOF-derivatives had great potential application for environmental protection.