Improving the catalytic activity in dry reforming reaction by enhancing the oxygen storage capacity of Ce_0.8Zr_0.2O₂ support through hydrogen heat-treatment

We provided a different atmosphere (20% H₂/N₂, N₂, and ambient air) during the heat-treatment of the Ce_0.8Zr_0.2O₂ support while preparing a Ni/Ce_0.8Zr_0.2O₂ catalyst. The difference in heat-treatment conditions affected the physicochemical properties of the support and catalyst. In particular, it strongly affected the oxygen storage capacity (OSC) of the Ce_0.8Zr_0.2O₂ support. Ni (5 wt%) was impregnated on each Ce_0.8Zr_0.2O₂ support heat-treated in different atmospheres, and the characterizations of each support and catalyst were also conducted. Interestingly, the dispersion of Ni⁰ in the catalyst showed a similar trend to the OSC of the support because of the anchoring effect. The dispersion of Ni⁰ mainly determined the catalytic activity of the dry reforming reaction in this study, not the OSC of the Ni impregnated catalyst. The characterization and catalytic reaction results revealed a deep relationship between the OSC of the support and the dispersion of Ni⁰, crystallite size of Ni⁰, and catalytic activity. The catalyst prepared with the support heat-treated in 20% H₂/N₂ showed the highest OSC of the support, highest Ni⁰ dispersion and smallest Ni⁰ crystallite size of the catalyst after impregnating Ni, resulting in the highest catalytic activity in the dry reforming reaction. This result suggests that the improvement of the catalytic activity by enhancing the OSC of the Ce_0.8Zr_0.2O₂ support is possible through hydrogen heat-treatment before the impregnation of Ni.