Inverse opal structured Pt/TiO2–MnOy photothermocatalysts for enhanced toluene degradation activity

Abstract

Photothermocatalysis is gaining increasing scientific attention for its potential in alleviating the ever-worsening volatile organic compound (VOC) pollution. Herein, we fabricated inverse opal (IO) structured TiO₂–MnO_y photothermocatalysts whose photothermocatalytic toluene degradation performance varied significantly at different Ti-to-(Ti + Mn) ratios. The rate constant for photothermocatalytic toluene degradation for the best TiO₂–MnO_y sample was 11.3 times and 12.1 times higher than that of the TiO₂ and MnO_y sample, respectively, reaching 0.03812 min⁻¹. This high activity arose from the IO structure which contained abundant macropores and contributed to enhancement of catalytic activity by enhancing light absorption and toluene adsorption capability. Deposition of Pt nanoparticles which were dual-functional photo-thermal (co)catalysts led to further enhancement of toluene degradation activity by promoting the toluene adsorption on the MnO_y surface and activating O₂ to form reactive oxygen species. Moreover, the formation of a Schottky junction between Pt and TiO₂ also enhanced the charge separation and utilization efficiency, allowing for more efficient generation of active species for toluene activation and catalyst re-oxidation for achieving high toluene degradation activity.