The promoting effect of H2O on rod-like MnCeOx derived from MOFs for toluene oxidation: A combined experimental and theoretical investigation

Abstract

Herein, a series of rod-like MnCeOx are synthesized by pyrolyzing Mn/Ce-BTC for toluene oxidation. The 3Mn2Ce catalyst exhibits superior catalytic performance and stability under high humidity (10 % H2O). XRD, Raman, H2-TPR, O2-TPD, XPS and EXAFS results confirm that the formation of solid solution between Ce and Mn species and better reducibility play a key role in toluene oxidation. H2O-TPD, toluene-TPD, toluene-TPSR, in situ DRIFTS in different conditions and TD-GC–MS confirm that the introduction of water can promote toluene mineralization. H2O-TPD indicates that oxygen vacancies adsorbed H2O to provide HOH active sites and promote the conversion of Oads to Olatt. The degradation pathway of toluene was toluene→benzaldehyde→benzoate→CO2 and H2O. Additionally, the water promotion is also confirmed by DFT calculations. The promotion of water vapor is that the water vapor is conducive to the adsorption of toluene, benzaldehyde and oxygen, and promotes the activation of oxygen.