Catalytic Decomposition of Methane to Hydrogen and Carbon Nanofibers over Ni−Cu−SiO2 Catalysts

Highly active and stable Ni−Cu−SiO2 catalysts are prepared by a coprecipitation method and are employed for direct decomposition of methane to hydrogen and carbon nanofibers at 650 °C and atmospheric pressure. The influence of Cu content is investigated over Ni−Cu−SiO2 samples with different Cu/Si ratios. The activity results revealed that a certain amount of Cu could enhance methane decomposition activity of Ni. The influence of catalyst calcination temperature is also explored, and it is concluded that calcination at 450 °C is enough for good catalytic performance of Ni−Cu−SiO2 samples. The physicochemical characteristics of fresh catalysts are characterized by BET-SA, X-ray diffraction (XRD), scanning electron microscopy–energy dispersive X-ray (SEM-EDX), temperature-programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS) analyses. The deactivated catalysts are analyzed by BET-SA, XRD, Raman, transmission electron microscopy (TEM), and carbon hydrogen nitrogen sulfur (CHNS) techniques. T...