Large amounts of anthropogenic VOCs emissions give rise to photochemical smog and ground-level ozone. Currently, catalytic oxidation for VOCs elimination still requires energy-intensive high temperatures. Light-driven photo-thermocatalysis oxidation of VOCs holds great promise to substantially reduce energy consumption for sustainable development in comparison with conventional thermal-based catalytic oxidation. Herein, CeO2/LaMnO3 composite, featuring the broad light wavelength absorption (800~1800?nm), can be used as a highly active photo-thermal responsive catalyst on VOCs decomposition under IR irradiation. The maximum photo-thermal conversion efficiency is able to reach 15.2% with a significant toluene conversion of 89% and CO2 yield of 87% under IR irradiation intensity of 280?mW/cm2, together with excellent stability of nearly 30?h. Comparative characterizations reveal that such photo-thermal catalytic activity enhancement is predominantly attributed to the synergistic effects of ultrabroadband strong light absorption, efficient light-to-heat conversion, good low temperature reducibility and high lattice oxygen mobility, originating from an intense interaction of LaMnO3 with CeO2. Toluene oxidation reaction on CeO2/LaMnO3 catalyst proceeds via a Mars-van Krevelen mechanism as evidenced by in situ diffuse reflectance infrared Fourier transform spectroscopy.
SEM and TEM images of (a) LaMnO3, (b, d) CeO2/LaMnO3 and (c) CeO2 (inset in (d) shows the high magnification TEM image); (e) The high-resolution TEM (HRTEM) images of the selected area in panel d (note that inset is a selected area electron diffraction (SAED) pattern and the right images of panels e are the fast Fourier transform (FFT) pattern of the area marked by the red and blue square box and the corresponding intensity profiles, respectively); and (f) TEM-EDX elemental mapping of La, Mn, Ce and O distribution of CeO2/LaMnO3 composite. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article).