CO₂ reforming of CH₄ using coke oven gas over Ni/MgO-Al₂O₃ catalysts: Effect of the MgO:Al₂O₃ ratio

Research is being actively conducted to improve the carbon deposition and sintering resistance of Ni-based catalysts. Among them, the Al₂O₃-supported Ni catalyst has been broadly studied for the dry reforming reaction due to its high CH₄ activity at the beginning of the reaction. However, there is a problem of deactivation due to carbon deposition of Ni/Al₂O₃ catalyst and sintering of Ni, which is a catalytically active material. Supplementing MgO in Ni/Al₂O₃ catalyst can result in an improved MgAl₂O₄ spinel structure and basicity, which can be helpful for the activation of methane and carbon dioxide molecules. In order to confirm the optimal supports’ ratio in Ni/MgO-Al₂O₃ catalysts, the catalysts were prepared by supporting Ni after controlling the MgO:Al₂O₃ ratio stepwise, and the prepared catalysts were used for CO₂ reforming of CH₄ (CDR) using coke oven gas (COG). The catalytic reaction was conducted at 800^◦C and at a high gas hourly space velocity (GHSV = 1,500,000 h⁻¹) to screen the catalytic performance. The Ni/MgO-Al₂O₃ (MgO:Al₂O₃ = 3:7) catalyst showed the best catalytic performance between prepared catalysts. From this study, the ratio of MgO:Al₂O₃ was confirmed to affect not only the basicity of the catalyst but also the dispersion of the catalyst and the reducing property of the catalyst surface.