The effect of CH4 decomposition temperature on the property of deposited carbon over Ni/SiO2 catalyst

•The activity and stability were dependent on the reaction temperature.•Ni/SiO2 catalyst showed the best initial activity at 700 °C.•The thinnest and densest whisker carbon formed at 700 °C.•The catalyst showed the highest catalytic stability at 550 °C.•The proportion of the defective carbon reduced with increased reaction temperature.

The activity and stability of Ni/SiO2 catalyst for the decomposition of methane at different temperature were investigated and the types of deposited carbon were also monitored. The catalyst was prepared by impregnation method and characterized by XRD, TG, SEM, Raman, TPH and TPO techniques. The dependence of the morphology, structure, and amount of deposited carbon over the used catalyst on the reaction temperature was studied. The results suggested that the Ni/SiO2 catalyst showed the best initial catalytic activity at 700 °C for the catalytic decomposition of methane, where the carbon whisker was the finest and densest, and the proportion of the well-ordered graphic was enhanced with increased reaction temperature. The largest amount of carbon deposition was observed at 550 °C used catalyst, and at this reaction temperature the Ni/SiO2 catalyst showed relatively the highest stability.

Graphical abstractOver 550 °C used catalyst, the thick whisker-like deposited carbon formed might keep the surface Ni species exposed, and therefore kept a better stability and activity, thus, the largest amount of carbon deposition was observed.Figure optionsDownload full-size imageDownload as PowerPoint slide