Methane decomposition over Ni/carbon catalysts prepared by selective gasification of coal char

Highlights: • H₂-rich gas and Ni/carbon hybrid are obtained by partial gasification of coal char. • Carbothermal reduction could enable in-situ formation of Ni⁰ crystallites. • The Ni/carbon hybrid is used as catalyst for methane decomposition. • High and stable methane conversion (up to about 90% at 850 °C) can be obtained. - Abstract: Catalytic methane decomposition (CMD) can pave the route for co-production of CO_x free hydrogen and valuable carbon materials, and it is considered as a potential promising strategy to develop eco-friendly and low-carbon hydrogen economy. However, there are still some challenges for utilization of traditional metal and/or carbon catalysts. In this work, relatively dispersed and efficient Ni/carbon catalysts were handily prepared for CMD by selective steam gasification of coal char with addition of nickel and/or cerium compositions. Carbothermal reduction during the gasification process could enable in-situ formation of Ni⁰ crystallites and facilitate the gasification efficiency and thus achieving co-production of hydrogen-rich gas and Ni/carbon hybrids with large surface areas (217–265 m²/g). When the Ni/carbon hybrids as the selective gasification residues were used for CMD, high and stable methane conversion (up to about 90% at 850 °C) can be obtained in the 600-min CMD reaction, thanks to the relatively dispersed and active Ni⁰ crystallites, large surface area of the porous carbon support and formation and growth of the fibrous carbon deposits.