Stability and Activity Enhancement Effects of Mn-Doped Ni-Al Catalysts for Thermocatalytic Methane Decomposition

The market demand for hydrogen is increasing steadily as hydrogen has emerged as a clean alternative to fossil fuels with low greenhouse gas emissions. More than 50% of global hydrogen is produced from steam reforming of methane, a high temperature, pressure, and carbon footprint process that requires large energy inputs, mostly from fossil fuels [1]. Thermocatalytic decomposition of methane or methane pyrolysis is an alternative process to produce COx free hydrogen with solid carbon as a by-product. Various catalysts (including metal, metal and metal oxide supported, and ceramic and carbon based) have been utilized in this process to decrease the high activation energy required to break the C-H bond. Among those, Ni catalysts over metal oxide support gained significant attention due to their low cost and high performance at low temperature. Recently, metal additives including Mn were shown to improve the stability and activity of Ni based catalysts prepared by impregnation method [2]. In this work, we explore the effect of Mn doping on the methane conversion yield and the catalyst stability prepared through Ni-Al hydrotalcite precursor using a differential fixed bed reactor. The catalyst is evaluated for methane decomposition at 550 °C until their complete deactivation. The deactivated catalysts and carbon by-products are examined by scanning electron microscopy, elemental analysis, and Raman spectroscopy. These analyzes contribute to understanding of material preparation-structure-property relationships towards methane decomposition reaction which will be discussed in this poster.

[1] Kaiwen, L.; Bin Y. &Tao Z. Economic analysis of hydrogen production from steam reforming process: A literature review. Energy sources, Part B: Economics, Planning, and Policy. 2018, 13:2, 109-115

[2] Wang, D.; Zhang, J.; Sun, J.; Gao, W.; Cui, Y. Effect of metal additives on the catalytic performance of Ni/Al2O3 catalyst in thermocatalytic decomposition of methane. International Journal of Hydrogen Energy. 2019, 44, 7205-7215