Effect of calcination temperature on structure and performance of Ni/TiO2-SiO2 catalyst for CO2 reforming of methane

The influence of calcination temperature on the structure and catalytic behavior of Ni/TiO2-SiO2 catalyst, for CO2 reforming of methane to synthesis gas under atmospheric pressure, was investigated. The results showed that the Ni/TiO2-SiO2 catalyst calcined at 700° C had high and stable activity while the catalysts calcined at 550 and 850° C had low and unstable activity. Depending on the calcination temperature, one, two, or three of the following Ni-containing species, NiO, Ni2.44Ti0.72Si0.07O4, and NiTiO3 were identified by combining the temperature programmed reduction (TPR) and X-ray diffraction (XRD) results. Their reducibility decreased in the sequence: NiO > Ni2.44Ti0.72Si0.07O4 > NiTiO3. It suggests that high and stable activities observed over the Ni/TiO2-SiO2 catalyst calcined at 700°C were induced by the formation of Ni2.44Ti0.72Si0.07O4 and smaller NiO species crystallite size.