Review and Outlook of Confined Ni Catalysts for the Dry Reforming of Methane Reaction

Dry reforming of methane (DRM) transforms greenhouse gases of CH4 and CO2 to syngas of H-2 and CO, which conduces to reducing emissions of the greenhouse gases and producing sustainable energy chemicals. Catalysts with confined structures can actively and stably catalyze DRM owing to their unique properties of the confinement effect, metal-support interaction, size effect, etc. The properties significantly contribute to resolve the problems of metal sintering and carbon deposition in DRM. This review summarizes the latest developments of confined Ni catalysts for DRM in recent years. The synthetic approaches of the confined catalysts are first introduced, followed by the achievements of DRM over Ni@M1Ox (M1Ox = SiO2, Al2O3, and ZrO2), Ni@zeolite (zeolite = SBA-15, MCM-41, and ZSM-5), bimetallic Ni-M-2@SiO2 (M-2 = Cu, In, and Co), and multifunctional (Ni/M3Ox)@SiO2 (M3Ox = CeO2, ZrO2, and Mg phyllosilicate). After illustration of the mono- and bifunctional mechanisms, the remarks and perspectives of DRM are proposed in the end. The review will shed light on fabricating other new confined catalysts for DRM and other reactions.