One-pot synthesis of a highly mesoporous Ni/MgAl₂O₄ spinel catalyst for efficient steam methane reforming: influence of inert annealing

A highly mesoporous Ni/MgAl2O4 spinel catalyst was facilely synthesized by a scalable one-pot strategy and employed in the steam methane reforming (SMR) reaction. The influence of annealing the catalyst in a N-2 atmosphere on its structural properties and catalytic performance is fully demonstrated for the first time. Physical characterization showed that subjecting the catalyst to an inert-annealing process (e.g., in a N-2 atmosphere) before calcining it in air enhances the specific surface area (SSA) and mesoporosity, improves the dispersion of Ni nanoparticles (NPs) within the support matrix, boosts the interaction between the active phase and support, and increases the content of the reduced Ni species on the catalyst surface. With its remarkable structural properties, the catalyst exhibits high CH4 conversion efficiency and durability as well as superb resistance to carbon deposition. These results reveal that the substructure and catalytic activity of the catalyst can be tuned by controlling the annealing conditions during the synthesis process. The straightforwardness of the synthesis strategy employed in this work makes it a promising route for designing catalysts with high coke-resistance in reforming and other high-temperature Ni-catalyzed reactions.