Photocatalytic Oxidation of Gaseous Toluene by Visible-Light-Driven CoCuMnO x : Performance and Mechanism

Abstract

CoCuMnO x as one solar energy absorbing coating was synthesized by a facile co-precipitation approach for photocatalytic oxidation of gaseous toluene under visible light, and characterized by UV–Vis-DRS, BET, SEM, XRD and XPS, respectively. It demonstrated that CoCuMnO x owned photocatalytic activity and 57% of toluene with an initial concentration of 400 mg/m3 was degraded by 1 g CoCuMnO x under 6 h irradiation with a 100 W halogen tungsten lamp. The degradation of toluene was mainly attributed to photolysis and photocatalysis, and the thermal effect of CoCuMnO x had little effect. The degradation efficiency of toluene decreased gradually from 57 to 32% after five consecutive cycles. High active spinels like Cu1.5Mn1.5O4, CuMn2O4, CuCoO2 and Co2MnO4 existed onto the CoCuMnO x surface, which accelerated electron transfer so as to form various free radicals, such as h+, .OH, and ·O2 − etc. Toluene was oxidized evidently by these radicals so that the aromatic ring itself was cleaved to generate alcoholic, aldehydic and acidic intermediates.