Oxygen defective bimodal porous Ni-CeO_2−x-MgO-Al₂O₃ catalyst with multi-void spherical structure for CO₂ reforming of CH₄

Ni-CeO₂-MgO-Al₂O₃ catalysts with bimodal meso-macropores have been synthesized by one-pot spray pyrolysis using dextrin as a structuring agent for dry reforming of methane. The formation of macropores originating from phase segregation and the decomposition of dextrin positively affects both the physical and chemical features of the catalysts, and therefore, the bimodal porous catalysts outperform the dense catalysts in catalytic activity and stability. The volume and size of macropores in a bimodal porous catalyst are dependent on the concentration of dextrin. Based on diverse characterization results, this morphological change has been revealed to induce the distortion of the CeO₂ lattice and embedding of Ni nanoparticles, resulting in the strong interaction between the metal and support/promoter and high oxygen storage capacity. The catalyst with balanced bimodal pore structures and optimized physicochemical parameters showed the best performance, considering both catalytic activity and stability with high sintering/coking resistance in the dry reforming of methane.