Dually Confined Ni-based Catalysts by Ion-Exchange Inverse Loading for Dry Reforming of Methane

Producing syngas from dry reforming of methane is fascinating but challenging because of coking and sintering. Herein, fine Ni nanoparticles surrounded by Al₂O₃ are constructed by ion-exchange inverse loading method. The dual confinement composed of physical barrier originated from Al₂O₃ surroundings and chemical bonding sourced from NiAl₂O₄ spinel is present on pitaya-like Ni@Al₂O₃ catalysts. Mixed acid–base property of Ni@Al₂O₃ mediates the co-conversion of CH₄ and CO₂. On the one hand, the acidity of Al₂O₃, accelerates the pyrolysis of CH₄. On the other hand, the basicity originated form ample O²⁻ promotes the chemisorption of CO₂ and oxidisation of carbon deposition using CO₂ as oxidiser. Based on the dual confinement and cooperation of acid–base sites, Ni@Al₂O₃ survive severe coking with a CO₂ conversion above 85% and no sign of deactivation. The metal-oxide interface is investigated focusing on physical–chemical confinement and properties, including electronic interaction, mixed acid–base property, and chemisorption of probe molecule.