Regulating Surficial and Interfacial Active Sites over Ce-Doped Alumina-Supported Ni Catalysts To Boost Low-Temperature CO 2 Methanation

Presently, low-temperature methanation with high CO 2 conversion levels at atmospheric pressure possesses significant energy efficiency and economic advantages. However, developing stable and high-performance non-noble-metal catalysts for low-temperature CO 2 methanation remains a formidable challenge. Herein, a novel strategy for the fabrication of cerium-doped alumina-supported Ni catalysts was developed via a facile one-step coprecipitation approach facilitated by a microliquid-film reactor. The as-constructed Ni/Ce–Al 2 O 3 catalyst featuring a Ce/(Ce + Al) molar ratio of 1:10 exhibited excellent low-temperature CO 2 methanation activity, with ∼82% CO 2 conversion and 100% methane selectivity at 250 °C and atmospheric pressure, as well as an extremely high methane production rate of 5.48 g CH4 ·g cat –1 ·h –1, suppressing those over most previously reported Ni-based catalysts. It was revealed that the introduction of a small amount of Ce favored the formation of abundant interfacial Ni δ+ sites and favorable surface Ce 3+ –O–Al structures, which effectively promoted the accommodation and migration of active hydrogen species and activated adsorption of CO 2, thereby facilitating the generation of key formate and CO intermediates and subsequent conversions to produce methane. This study provides a new approach for the construction of high-performance Ni-based catalysts for low-temperature CO 2 methanation and gives deep insight into the critical roles of surficial/interfacial active structures in boosting CO 2 hydrogenation to produce methane.