Construction of the Low-Loading Ni/CeO₂ Catalyst with a Boosted CO₂ Methanation Performance via the Facile Pyrolysis CeO₂ Support

Ni-loaded CeO₂-based materials are one type of the promising catalyst for CO₂ methanation; however, lowering the Ni loading, simplifying the preparation process of CeO₂ supports, and improving the low-temperature catalytic performance are always essential for scalable applications. Herein, an efficient CeO₂ support (CeO₂-NC) with a large inner pore size was prepared by a facilely controlled calcination of cerium nitrate [Ce­(NO₃)₃·6H₂O] method. On the basis of CeO₂-NC, one catalyst (Ni/CeO₂-NC) with low Ni loading (2.56 wt %), desirable Ni dispersity, and abundant medium basic sites was developed that exhibited the amazing low-temperature CO₂ methanation performance. At 275 °C, CO₂ conversion reached up to 77.7% with an almost 100% CH₄ selectivity under a high gas hourly space velocity of 60000 mL g_cat^–1 h^–1, and the Ni-based mass-specific CH₄ formation rate at 300 °C was up to 4740 μmol g_Ni^–1 s^–1, outperforming most of the reported Ni-based catalysts to date. The in situ diffuse-reflectance infrared Fourier transform spectroscopy experiments revealed that plentiful active bidentate carbonate intermediates and effective suppression of the dissociated active H species recombination contributed to the boosted CO₂ methanation performance of Ni/CeO₂-NC at low temperatures. Moreover, the mechanism was also inferred. This work provides new insight into simple pyrolysis CeO₂ supports and should be of significance for the rational design of highly efficient CO₂ methanation catalysts.