Characteristics of CeO2–ZrO2 mixed oxide prepared by continuous hydrothermal synthesis in supercritical water as support of Rh catalyst for catalytic reduction of NO by CO

CeO2–ZrO2 mixed oxides were prepared by continuous hydrothermal synthesis in supercritical water (supercritical synthesis) and co-precipitation method, respectively, and they were used as support for Rh catalyst. The activities of Rh-loaded CeO2–ZrO2 catalysts were investigated for catalytic reduction of NO by CO and their physicochemical properties were characterized with TPR, N2 adsorption, O2-uptake, XRD, Raman, SEM, AES, and H2/CO chemisorption. Discussions were made on the differences in the catalytic performances between the two preparation methods of CeO2–ZrO2 supports in terms of reducibility, homogeneity, morphology, Rh dispersion, and thermal stability. Rh-loaded CeO2–ZrO2 prepared by supercritical synthesis showed superior performances for the catalytic reduction of NO by CO as well as better reducibility and higher thermal stability, compared with co-precipitation method, due to its sparsely-agglomerated morphology. CeO2–ZrO2 mixed oxide prepared by supercritical synthesis had more potential applications as catalyst support mainly due to its sparsely-agglomerated morphology and higher thermal stability.