Insight into the role of material basicity in the coke formation and performance of Ni/Al2O3 catalyst for the simulated- biogas dry reforming

Abstract

Biogas, a mixture of methane and carbon dioxide produced from microbial digestion of biomass, waste, or residues, has gained increasing attention from scientists as a valuable resource for producing syngas. This study investigated the effects of different promoters, including calcium, copper, and chromium compounds, on the performance of nickel-based catalysts in biogas reforming. The catalysts were prepared by co-impregnating nickel precursors with the promoters onto the support using the incipient wetness method. The addition of calcium and chromium oxides improved nickel dispersibility, enhanced reducibility, and provided adequate basicity, resulting in superior catalytic activity. Among the promoted catalysts, 0.1Ca–1Ni/Al2O3 demonstrated the best performance with 72% CH4 and 74% CO2 conversions and no significant loss in catalytic activity after 6 h. Additionally, the study found that the basicity of the material was proportional to the transition of amorphous coke into graphitic type, and the advantages and disadvantages of each type of coke were thoroughly discussed.