LAUSR

Abstract Manganese oxides (MnOx) are one kind of the most used thermo-catalysts for catalytic oxidation of gaseous organic pollutants, but this process will cause excessive energy consumption. Herein, the photothermal effect of graphene oxide (GO) was utilized to convert the inexpensive solar energy to thermal energy, which subsequently drives the thermo-catalysis of MnOx for degrading gaseous formaldehyde at ambient condition. For achieving high thermal conducting ability, an intimately hybridized 2D/2D composite of GO/MnOx was hydrothermally prepared. Comparing with the GO, the MnOx and the mechanically mixed GO/MnOx, the hydrothermally synthesized composite exhibited significantly improved performance for HCHO removal under the xenon lamp illumination, and the HCHO concentration was rapidly decreased from ∼160 ppm to ∼10 ppm in 20 min. Experimental results using different illumination conditions indicated that the photothermal conversion was mainly from near infrared radiation (NIR). The Mars-van Krevelen mechanism was employed to explain the catalytic process of HCHO removal, where the adsorbed oxygen molecule and lattice oxygen atom were simultaneously activated under irradiation. This work develops an excellent catalyst for effective removal of HCHO, and meanwhile demonstrates that combination of carbonaceous materials with high photothermal conversion capability is a promising strategy to promote the low-temperature catalytic performance of thermo-catalysts.