Efficient UV-vis-IR light-driven thermocatalytic purification of benzene on a Pt/CeO2 nanocomposite significantly promoted by hot electron-induced photoactivation

Abstract

Complete oxidation of volatile organic compounds (VOCs) as major air pollutants on supported noble metal catalysts is a very important industrial reaction for environmental purification. It is highly desirable but greatly challenging to find a green process with low energy consumption and high catalytic efficiency for VOC abatement by using renewable solar energy. Here, we achieve highly efficient catalytic oxidation of benzene (one of the typical VOCs) on a nanocomposite of Pt nanoparticles partially confined in the mesopores of microsized mesoporous CeO₂ (Pt/CeO₂-MM) with the irradiation of full solar spectrum or visible-infrared light, even with infrared light irradiation. The highly efficient catalytic activity arises from the solar light-driven thermocatalysis on Pt/CeO₂-MM due to the excellent thermocatalytic activity and the local heating effect induced by strong surface plasmonic absorption of the Pt nanoparticles in the entire solar spectrum region from 200 to 2500 nm. Remarkably, it is found that a novel hot electron-induced photoactivation process significantly enhances the solar light-driven thermocatalytic activity. In situ FTIR in the dark and with solar light irradiation reveals that the hot electron-induced photoactivation of benzene adsorbed on the Pt nanoparticles in Pt/CeO₂-MM plays a decisive role in the catalytic enhancement.