Impact of Zr on the Activity of MoO3/Ce1-xZrxO2 Catalysts for Sulfur-Resistant Methanation

In this work, ZrO2-modified MoO3/CeO2 catalysts were prepared and applied in the sulfur-resistant methanation reaction. Roles of Zr on the structural characteristics and the catalytic activity were systematically investigated. The introduction of ZrO2 into CeO2 matrix, which caused the presence of ZrO2/CeO2 solid solution, contributed to the generation of a large amount of Ce3+ species accompanied by defect oxygen under reductive conditions. The defect oxygen can significantly enhance oxygen mobility of the support, which leads to the well dispersed active MoS2 evolving from the easier reduction of Mo-species by increased reducible Ce3+. Among all studied catalysts, MoO3/Ce0.8Zr0.2O2 exhibited the best catalytic performance because of the highly dispersed MoS2 and surface Ce3+ species, two key active sites in sulfur-resistant methanation reaction. The concurrence of CO hydrogenation and water-gas shift reaction is also one of the prerequisites to achieve higher catalytic performance.