Solvent-free catalytic oxidation of toluene over heterogeneous CeMnOx composite oxides

An inexpensive and controllable CeMnOx composite oxides catalyst for the liquid-phase catalytic oxidation of toluene was conveniently prepared by ultrasound-assisted co-precipitation method. The physical–chemical properties of CeMnOx composite oxides catalyst have been systematically characterized. MnOx as catalytic active species was highly dispersed in the cubic fluorite structure CeO2. The cooperation of CeO2 and MnOx evidently improved the catalytic performance. CeMnOx composite oxides with a Ce/Mn molar ratio of 2:1 was showed the good catalytic performance. 7.0% of toluene conversion and 95.6% of overall selectivity to benzylalcohol, benzaldehyde and benzoic acid was acquired under optimal reaction conditions. The present catalyst has the advantages of low cost, good catalytic performance and stability. This work provides a simple, benign and controllable approach for the selective oxidation of toluene to valuable oxidation products.Graphical abstract