Customized Ni-MgO-ZrO₂catalysts for the dry reforming of methane using coke oven gas: Optimizing the MgO content

Ni-ZrO2 and Ni-MgO-ZrO2 catalysts were prepared by the stepwise control of the MgO content in the Ni-ZrO2 catalyst to develop a customized catalyst for the dry reforming (DRM) reaction utilizing coke oven gas (COG). The difference in MgO content affected the physicochemical properties of the catalysts. As MgO was added and the amount increased, formation of the NiO-MgO solid solution was promoted, so the Ni0 dispersion increased, but the reduction degree decreased due to strong metal-support interactions. On the other hand, basicity of the catalyst was not simply enhanced as the MgO content increased but was also affected by the degree of incorporation of Mg2+ ions into the tetragonal-ZrO2 lattice. We systematically changed the MgO content to select a catalyst that could show excellent performance in the actual process, while applying the catalyst to various reaction tests. Reaction conditions for screening of catalytic performances were derived by calculating thermodynamic equilibrium to minimize carbon deposition and maximize CO yield. As a result of catalytic evaluation, the Ni-30MgO-ZrO2 catalyst exhibited the highest catalytic activity and stability in the COG-DRM reaction. In addition, the Ni-30MgO-ZrO2 catalyst showed high stability through a long-term stability test and a temperature swing test (800-900 °C), indicating the possibility of commercialization for the target reaction.