Insights into the superior performance of mesoporous MOFs-derived Cu-Mn oxides for toluene total catalytic oxidation

A novel approach is developed to synthesize a series of flower like CuMn oxides catalysts for toluene removal with high efficiency. The optimal catalyst (i.e., 1Cu1Mn-450 prepared by calcination of Cu1Mn1-ptcda MOFs with Cu/Mn molar ratio of 1:1 by 450 degrees C) maintains 100% toluene removal for 54 h in the presence of steam (5.0 Vol%) at 210 degrees C. Besides, 1Cu1Mn-450 displays superior catalytic activity at high WHSV and high toluene concentrations. The relationships between textural, structural, and toluene catalytic performance are analyzed by various characterization techniques. Due to strong low-temperature reducibility, mobility of active oxygen, high average oxidation states (AOS) of Mn, mobility of active oxygen, as well as oxygen storage capacity at low temperatures, 1Cu1Mn-450 exhibits excellent activity and stability of toluene oxidation. The toluene oxidation was in the following pathway of toluene -> alkoxide -> benzoate -> phenolate -> maleic anhydride -> short-chain carboxylates -> CO2 and H2O. The breakage of CO in benzoate or CC in benzene ring is proved to be the rate-controlled step according to in situ DRIFTS. These findings can provide a feasible method to desigin transition metal oxide catalysts for large-scale industrial applications.

Automated summary

A novel approach is developed to synthesize flower-like CuMn oxides catalysts for efficient toluene removal. The optimal catalyst, 1Cu1Mn-450, exhibits 100% toluene removal for 54 hours in the presence of steam at 210 degrees C. It shows excellent catalytic activity and stability due to its strong low-temperature reducibility, mobility of active oxygen, high average oxidation states of Mn, and oxygen storage capacity at low temperatures. The toluene oxidation follows a specific pathway, and the rate-controlled step is the breakage of CO in benzoate or CC in benzene ring.