Eun-Yong Ko

Selective CO oxidation in the presence of hydrogen over supported Pt catalysts promoted with transition metals

Selective CO oxidation in the presence of excess hydrogen was studied over supported Pt catalysts promoted with various transition metal compounds such as Cr, Mn, Fe, Co, Ni, Cu, Zn, and Zr. CO chemisorption, XRD, TPR, and TPO were conducted to characterize active catalysts. Among them, Pt-Ni/γ-Al2O3 showed high CO conversions over wide reaction temperatures. For supported Pt-Ni catalysts, Alumina was superior to TiO2 and ZrO2 as a support. The catalytic activity at low temperatures increased with increasing the molar ratio of Ni/Pt. This accompanied the TPR peak shift to lower temperatures. The optimum molar ratio between Ni and Pt was determined to be 5. This Pt-Ni/γ A12O3 showed no decrease in CO conversion and CO2 selectivity for the selective CO oxidation in the presence of 2 vol% H2O and 20 vol% CO2. The bimetallic phase of Pt-Ni seems to give rise to stable activity with high CO2 selectivity in selective oxidation of CO in H2-rich stream.

ZrO2-supported Pt catalysts for water gas shift reaction and their non-pyrophoric property

Zirconia-supported platinum catalysts doped with cerium, nickel or cobalt (Pt-Ce/ZrO 2 , Pt-NilZrO 2 , Pt-Co/ZrO 2 ) were prepared by a single step co-impregnation method and their catalytic performance on the water gas shift reaction (WGS) were investigated. A Pt/Ce/ZrO 2 catalyst was also prepared impregnating ZrO 2 sequentially with Pt and Ce in order to compare the effects of impregnation methods on the catalytic activities of the final form of the catalysts. The results showed that the co-impregnated Pt-Ce/ZrO 2 catalyst was highly active for the WGS reaction at low temperatures (250 °C, GO conversion of 95.1%, feed composition of 10 vol% CO, 10 vol% CO 2 , and 80 vol% H 2 in dry base gas, H 2 O/CO=6, GHSV= 6000 h -1 ) and kept its activity even after air exposure in every cyclic test. The temperature programmed reduction (TPR) pattern of Pt-Ce/ZrO 2 indicated that the low reduction temperature of Pt induced by Ce gave rise to high activity on the WGS reaction. This Pt-Ce/ZrO 2 catalyst can be considered as an efficient catalyst for the WGS reaction, where high catalytic activity and non-pyrophoric property were required.