Effect of surface properties of Ni-MgO-Al₂O₃ catalyst for simultaneous H₂ production and CO₂ utilization using dry reforming of coke oven gas

We designed the customized Ni-MgO-Al₂O₃ catalyst for the dry reforming of methane (DRM) using coke oven gas (COG). The calcination conditions of the catalysts were systematically controlled to investigate the effect of the surface properties of the catalysts on catalytic performance. The characterization results showed that the physicochemical properties of the catalyst, such as basicity, BET surface area, Ni dispersion, Ni crystallite size, and reducibility varied with the calcination temperature. Considering the gas composition of the COG, the operating conditions were also optimized by calculating thermodynamic equilibrium to maximize the CO yield and minimize carbon deposition. As a result of catalytic evaluations conducted at selected operation conditions, we found that the catalytic activity is strongly affected by the number of Ni active sites correlated with the Ni dispersion and reduction degree. In addition, the basicity of the catalyst played an important role in CO₂ adsorption and activation, which is related to coke resistance. Among the prepared catalysts, the Ni-MgO-Al₂O₃ (calcination temperature = 800 °C) catalyst exhibiting best catalytic performance due to a large number of Ni active sites and relatively good basicity, was selected as the optimal catalyst, and the possibility of commercialization was confirmed through the long-term stability test and start-up/shut-down test.