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

Abstract

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, N-2 adsorption, O-2-up-take. XRD, Raman, SEM, AES, and H-2/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. (C) 2009 Elsevier Inc. All rights reserved.