Pyrolysis of methane is a carbon-economic method to obtain valuable carbon materials and COx- free H2, under the carbon peaking and carbon neutrality goals. In this work, we propose a methane pyrolysis process to produce graphite and H2 using bubble column reactor containing NiO/Al2O3 and NaCl–KCl (molten salt). The process was optimized by the different amounts of NaCl–KCl, the CH4/ Ar ratio and temperature, indicating that the CH4 conversation rate could reach 92% at 900 °C. Meanwhile, we found that the addition of molten salt could obtain pure carbon materials, even if the conversation rate of CH4 decreases. The analysis of the carbon products revealed that graphite could be obtained.

NiO catalysts/Al2O3/FeCrAl alloy foam for hydrogen production was prepared using atomic layer deposition (ALD)and subsequent dip-coating methods. FeCrAl alloy foam and Al2O3 inter-layer were used as catalyst supports. To improve thedispersion and stability of NiO catalysts, an Al2O3 inter-layer was introduced and their thickness was systematically controlledto 0, 20, 50 and 80nm using an ALD technique. The structural, chemical bonding and morphological properties (includingdispersion) of the NiO catalysts/Al2O3/FeCrAl alloy foam were characterized by X-ray diffraction, X-ray photoelectronspectroscopy, field-emission scanning electron microscopy and scanning electron microscopy-energy dispersive spectroscopy. Inparticular, to evaluate the stability of the NiO catalysts grown on Al2O3/FeCrAl alloy foam, chronoamperometry tests wereperformed and then the ingredient amounts of electrolytes were analyzed via inductively coupled plasma spectrometer. We foundthat the introduction of Al2O3 inter-layer improved the dispersion and stability of the NiO catalysts on the supports. Thus, whenan Al2O3 inter-layer with a 80nm thickness was grown between the FeCrAl alloy foam and the NiO catalysts, it indicatedimproved dispersion and stability of the NiO catalysts compared to the other samples. The performance improvement can beexplained by optimum thickness of Al2O3 inter-layer resulting from the role of a passivation layer.