Effect of citric acid addition on MoO3/CeO2-Al2O3 catalyst for sulfur-resistant methanation

Citric acid hold great promise to improve the Mo-based catalyst performance for hydrogenation reaction applications. MoO3/CeO2-Al2O3 catalysts were prepared by impregnation method with adding citric acid into CeO2-Al2O3 composite supports and tested for sulfur resistant methanation. The syngas methanation activity increased with the increase of citric acid additive amount, and CO conversion could reach up 60% when the molar ratio of citric acid to Ce was 3. The prepared catalysts were characterized by BET, H2-TPR, XRD and XPS. The increased catalytic performance was mainly attributed to the increased amount of Ce species on the surface of catalysts which could decreased the interaction force between MoO3 and CeO2-Al2O3 supports. Additionally, the increased specific surface of CeO2-Al2O3 composite support was also in favor of catalytic performance.