Deciphering the Role of Nickel Loading in the Bi-Reforming of Methane Over Ni/CeO₂ Catalyst

Bi-reforming of methane (BRM), a synergistic process integrating carbon dioxide (CO₂) and steam reforming of methane (CH₄), presents a promising route for the valorization of greenhouse gases (CH₄ and CO₂) into synthesis gases. The current research elucidates the correlation between Ni loading levels and the resulting physicochemical attributes and catalytic behavior of Ni catalyst supported on CeO₂ designed for BRM process. This study involved the synthesis of Ni/CeO₂ catalysts using ultrasonic-assisted impregnation method with Ni loading range of 5 to 15 wt% and characterized using BET, XRD, FESEM-EDX, ICP-OES, FTIR, CO₂-TPD, H₂-TPR, and TPO. The catalytic performance of synthesized catalysts was assessed in a fixed bed reactor (WHSV = 36,000 mL/g·h, P = 1 atm, and T = 800 °C) for 8 h. The efficiency of reactant conversion scaled proportionally with Ni content, exhibiting a clear loading-dependent trend in the following sequence: 15 > 10 > 5 wt% Ni/CeO₂. Notably, the 15 wt% variant demonstrated excellent BRM catalytic performance, achieving CH₄, and CO₂ conversion of more than 70%, along with 45% of H₂ yield production. In conclusion, the study demonstrated that the Ni contents act as a decisive factor in modulating both chemical behavior and the structural integrity in Ni/CeO₂ catalysts during the BRM reaction.