Preparation and characterization of P-Mo-V mixed oxide-incorporating mesoporous silica catalysts for selective oxidation of methane to formaldehyde

摘要

P-Mo-V mixed oxide-incorporating mesoporous silica catalysts with different contents were prepared by a template method with Keggin-type heteropoly acid(HPA),H5PMo10V2O40,under acidic conditions,followed by calcination at 873 K for 5 h.During the preparation,the HPA used as a precursor of the oxide acted as a co-acid of HCl that controlled the acidity of the starting mixture.The catalysts were characterized by thermal analysis,X-ray diffraction,X-ray fluorescence spectroscopy,N2 adsorption,transmission electron microscopy,and Raman spectroscopy.The results indicated that the framework of P-Mo-V incorporated mesoporous silicas was similar to that of MCM-48.The molar ratio of P:Mo:V(1:10:2)in the catalysts showed no significant change from the HPA precursor and the mixed oxides were highly dispersed below 6.68 wt% content.The catalysts showed good activity in the selective oxidation of methane to formaldehyde with oxygen.