Chemical looping-based catalytic CH₄ decomposition and successive coke gasification with CO₂ on ordered mesoporous NiMCeOx (M = Co, Zr, La)

Highly ordered mesoporous NiLaCeOx mixed metal oxides were investigated as effective catalysts for the chemical looping-based dry reforming of methane (CH₄) with carbon dioxide (CO₂) (CL-DRM). This catalyst exhibited an excellent catalytic activity and stability in the decomposition of CH₄ to form H₂ with surface carbons subsequently activated by CO₂ via reverse Boudouard reaction to form CO. Among the NiMCeOx catalysts with various promoter (M = Co, Zr, or La), the optimal NiLaCeOx catalyst preserved its original highly ordered mesoporous structures, leading to the higher dispersion of smaller Ni nanoparticles. This was attributed to the stronger Ni-Ce interactions facilitated by the La₂O₃ metal oxide promoter. The NiLaCeOx demonstrated a higher rate of H₂ formation and successive CO production in the CL-DRM reaction, resulting in a H₂/CO ratio above 1.0. Additionally, the NiLaCeOx catalyst exhibited superior structural stability over 5 cyclic CL-DRM reactions for CH₄ decomposition (>85 %) and CO₂ activation (>45 %), with minimal deposition of cokes.