Hierarchically MnO2/SiO2 nanocomposites with high solar light-driven photo-thermo catalysis activity for efficient toluene removal

Catalytic oxidation of toluene by employing manganese dioxide (MnO 2 ) as catalysts has shown great potential, however, the huge energy demands during the MnO 2 catalytic process limits its application. Herein, a new type of MnO 2 /SiO 2 nanocomposites with outstanding solar light-driven photo-thermo catalysis activity was successfully fabricated. The MnO 2 nanoparticles in homogeneous dispersion state were decorated on the surface of SiO 2 nanofiber. The abundant hydroxyl groups on the surface of SiO 2 nanofiber facilitated toluene enrichment. Moreover, abundant oxygen vacancies were generated through the substitution between the Mn 4+ and Si 4+ , which improved the concentration and mobility of active oxygen. An excellent photo-thermo catalytic activity of MnO 2 /SiO 2 nanocomposites on toluene degradation was observed with a significant CO 2 yield (100 %) and high value of CO 2 production rate under simulated sunlight, which was much superior to that of P25 and MnO 2 powders. The mechanism of the enhanced catalytic performance of MnO 2 /SiO 2 nanocomposite is ascribed to the synergism of photo-activation and solar light-driven thermo-catalytic oxidation. This work demonstrates a new route to develop MnO 2 -based photo-thermo catalyst and provides an energy-saving way for toluene removal on overall utilization of solar energy.