Promoting Effects of Ni for Toluene Catalytic Combustion Over CoNi/TiO2 Oxide Catalysts

The supported CoNi/TiO2 composite oxide catalysts were prepared by impregnation method. The physical and chemical properties of the prepared catalysts were studied by XRD, XPS and H-2-TPR. The results show that the Co3O4 , NiO and NiCo2O4 species are formed in the CoNi/TiO2 composite oxide catalysts. The interaction between the Co and Ni species can effectively enhance the properties of the CoNi/TiO2 oxide catalysts. The introduction of Ni species can effectively enhance the surface hydroxyl oxygen species and adsorbed oxygen species content, and the Co3+ species content can be enhanced on the surface of the prepared CoNi/TiO2 composite oxide catalysts. The low temperature reducibility and toluene catalytic combustion activity of the CoNi/TiO2 composite oxide catalysts can be improved by the Ni species. The toluene catalytic combustion activity of CoNi/TiO2 composite catalysts can be obviously affected by the Co/Ni molar ratio. The CoNi/TiO2 composite oxide catalyst, which has a Co/Ni molar ratio of 1.0, has the best toluene catalytic combustion activity and wide scope of the concentration of toluene. The toluene catalytic combustion conversion can exceed 99 % at 340 degrees C. That is to say, the toluene concentration in air can be decreased to 80 ppm from 8000 ppm.