Efficient UV–vis-infrared light-driven catalytic abatement of benzene on amorphous manganese oxide supported on anatase TiO2 nanosheet with dominant {001} facets promoted by a photothermocatalytic synergetic effect

Abstract

The nanocomposites of amorphous manganese oxide (MnOx) supported on anatase TiO2 nanosheet with dominant {001} facets (TNS) with different Mn/Ti molar ratio were prepared by hydrothermal redox reaction of KMnO4 and Mn(NO3)2 in the presence of TNS. The MnOx/TNS nanocomposites were characterized by XRD, SEM, TEM, ICP, XPS, BET, and diffuse reflectance UV–vis-Infrared adsorption. MnOx/TNS with the optimum Mn/Ti molar ratio of 0.40 exhibits highly efficient photothermocatalytic activity and excellent durability for the oxidation of the recalcitrant and carcinogenic benzene under the full solar spectrum irradiation from a Xe lamp. Remarkably, the CO2 production rate of MnOx/TNS enhances by 99 times as compared to TNS. Impressively, MnOx/TNS also exhibits efficient photocatalytic activity with the visible-infrared irradiation, even with the infrared irradiation. The highly efficient photothermocatalytic activity of MnOx/TNS under the full solar spectrum irradiation originates from the highly efficient solar light-driven thermocatalysis on MnOx due to its strong absorption in entire solar spectrum region and the efficient thermocatalytic activity, which is considerably promoted by a photothermocatalytic synergetic effect. We put insight into the photothermocatalytic synergetic effect by CO temperature-programmed reduction of MnOx/TNS in dark and with the solar light irradiation: the active species generated by the photocatalysis on TNS migrate to MnOx via the MnOx/TiO2 interface, and accelerate the solar light-driven thermocatalysis on MnOx in the nanocomposite.