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.

Insights into carbon formation over molten salt-promoted NiOAl2O3 during methane pyrolysis
    Abstract
    1 Introduction
    2 Experimental
        2.1 Materials
        2.2 Melt pyrolysis of methane process
    3 Results and discussion
        3.1 Performance of the NiOAl2O3 catalyst in molten NaCl–KCl
        3.2 Analysis of carbon product
    4 Conclusion
    Acknowledgements 
    References

• Yangdong He(Research Institute of Natural Gas Technology, PetroChina Southwest Oil and Gasfield Company, Chengdu 610213, China)
• Xingsheng Jing(PetroChina Southwest Oil and Gasfield Company, Chengdu 610051, China)
• Li Qin(Southern Sichuan Gas District, PetroChina Southwest Oil and Gasfield Company, Luzhou, Sichuan, China)
• Dan Wang(Research Institute of Natural Gas Technology, PetroChina Southwest Oil and Gasfield Company, Chengdu 610213, China)
• Chen Wu(Research Institute of Natural Gas Technology, PetroChina Southwest Oil and Gasfield Company, Chengdu 610213, China)
• Mengying Liu(School of New Energy and Materials, Southwest Petroleum University, Chengdu 610500, China)
• Mingkai Yang(School of New Energy and Materials, Southwest Petroleum University, Chengdu 610500, China)
• Zeai Huang(School of New Energy and Materials, Southwest Petroleum University, Chengdu 610500, China) Corresponding author