Insights into the solar light driven thermocatalytic oxidation of VOCs over tunnel structured manganese oxides

Abstract

Different tunnel structured manganese oxides (1*1, 2*2, and 3*3) have been synthesized via a facile hydrothermal strategy. The three catalysts exhibit high photothermal performance, resulting in a considerable increase of temperature above the light-off temperature for VOC oxidation. On this point, aerobic oxidation reactions of propane and propylene under simulated sunlight and infrared light irradiation were selected as probe reactions to explore their light driven thermocatalytic activity. Furthermore, the light-off curves of the manganese oxides for propane and propylene were carefully investigated, which clearly explained the possibility of combining both the efficient photothermal effect and excellent thermocatalytic activity of the manganese oxides. Results show that the catalytic effects follow the order of 1*1 < 3*3 < 2*2. 2*2 exhibited the best catalytic properties due to better low-temperature reducibility, suitable tunnel structure and the presence of more Mn⁴⁺. This work suggests new applications for traditional catalysts with intense photoabsorption and provides insights into the overall utilization of solar energy.