Highly Efficient LaxCe1–xO2–x/2 Nanorod-Supported Nickel Catalysts for CO Methanation: Effect of La Addition

A group of ternary LaxCe1–xO2–x/2 nanorods with varying La/Ce ratios have been prepared by the hydrothermal strategy and further used to synthesize supported nickel catalysts for CO methanation. The optimal Ni/La0.15Ce0.85O1.925 catalyst showed remarkably improved activity and excellent resistance against coke formation compared with Ni/CeO2. The characterization results demonstrated that doping of La2O3 into CeO2 resulted in decreased grain size of Ni particles and increased Ni electron cloud density induced by the creation of more oxygen vacancies due to substituting La3+ for Ce4+, which were responsible for accelerating CO dissociation and eventually improved CO methanation activity. More importantly, the enhanced oxygen vacancies were helpful to improve the anticoking properties through eliminating the deposited carbon species. These studies shed light on the design of a catalyst with both outstanding activity at low temperatures and reliable stability at high temperatures for the CO methanation reaction.