Robust stability of CH4 cracking to CNTs and H2 over hydrotalcite-derived NiCuCrAl catalyst dependent on element induced Ni metal size

Catalytic decomposition of CH 4 is expected to yield pure hydrogen and carbon, which is important for reducing greenhouse gas emissions. Nickel-based catalyst are currently the most common catalyst for methane cracking but sintering and carbon accumulation can cause catalyst deactivation. Therefore, stabilizing the particle size of nickel-based catalysts by enhancing the metal-support interaction is crucial for designing methane cracking catalysts. In this study, the effect of added Cr and Cu on the performance of NiAl catalyst was studied. The results indicated that the co-doping of Cu and Cr improved the metal-support interaction and promoted the formation of oxygen vacancies. Cu doped NiAl catalyst increased the Ni–Ni bond length and decreased the coordination of Ni–Ni by alloying with Ni. This effectively stabilized the catalyst size during the CH 4 cracking reaction. It was showed that the smaller the variation in particle size of the catalyst during the reaction, the higher the stability of methane decomposition. The Ni 2.4 Cu 0.3 Cr 0.3 Al catalysts retained 60 % hydrogen yield for up to 630 min at 600 °C. By coupling “hydrogen preparation” and “carbon production”, this paper is expected to open up a new path for the integration of clean energy production and advanced carbon materials manufacturing in a resource-efficient and environmentally friendly way.