Highly efficient UV-Vis-infrared catalytic purification of benzene on CeMnxOy/TiO2 nanocomposite, caused by its high thermocatalytic activity and strong absorption in the full solar spectrum region†
Abstract
The nanocomposite of amorphous cerium manganese oxide supported on nano TiO2 (CeMnxOy/TiO2) was prepared by the facile hydrothermal redox reaction of Ce(NO3)3 and KMnO4 in the presence of nano TiO2. The CeMnxOy/TiO2 nanocomposite was characterized by XRD, TEM, SEM, EDX, XPS, BET, CO-TPR, and diffusive reflectance UV-Vis-IR absorption. It exhibits efficient thermocatalytic activity for the oxidation of the carcinogenic and recalcitrant benzene, which is comparable to that of the expensive noble metal catalyst (0.5% Pt/Al2O3), and is much higher than the CeO2/TiO2 and MnOx/TiO2 nanocomposites with the same metal/Ti molar ratio. Its specific CO2 production rate (rCO2) at 220 °C (88.6 μmol g−1 min−1) is 6.3 and 7.5 times higher than the nanocomposites of CeO2/TiO2 and MnOx/TiO2, respectively. The highly efficient thermocatalytic activity of the CeMnxOy/TiO2 nanocomposite is attributed to its higher oxygen activity, compared to the nanocomposites of CeO2/TiO2 and MnOx/TiO2. Remarkably, the CeMnxOy/TiO2 nanocomposite can be driven by simulated solar light for benzene oxidation. It exhibits highly efficient catalytic activity with the irradiation of the full solar spectrum, visible-infrared, and infrared light. Its initial CO2 production rate is 117.0, 94.8 and 37.9 μmol g−1catalyst min−1, under the irradiation of the full solar spectrum, visible-infrared light with wavelength above 420 nm, and infrared light with wavelength above 830 nm, respectively. This is attributed to the fact that the CeMnxOy/TiO2 nanocomposite efficiently transforms the absorbed solar energy into thermal energy, due to its strong absorption in the full solar spectrum region, resulting in a significant increase in its temperature above its light-off temperature, for the thermocatalytic oxidation of benzene.