화학공학소재연구정보센터
Applied Catalysis A: General, Vol.347, No.1, 34-42, 2008
Novel methanol steam reforming activity and selectivity of pure In2O3
Electron-microscopy suitable In2O3 thin films prepared by thermal deposition of In2O3 powder in 10(-2) Pa O-2 at 600 K and, for comparison, a commercial polycrystalline In2O3 powder catalyst were tested in methanol steam reforming and in both routes of the water-gas shift reaction as a function of reaction temperature. The effect of oxidative (1 bar O-2, 373-673 K, 1 h) and reductive (1 bar H-2, 373-673 K, 1 h) catalyst pre-treatments was assessed. The resulting structural and morphological changes occurring during catalyst activation and catalytic reaction were monitored by (high-resolution) transmission electron microscopy. scanning electron microscopy and surface area measurements by N-2 adsorption according to BET. Both the In2O3 thin film and the powder sample were observed to be structurally stable under typical catalyst pre-treatments in oxygen and hydrogen at temperatures T <= 673 K and T < 673 K, respectively, as well as under typical methanol steam reforming conditions at temperatures T <= 680 K. No pronounced catalyst sintering was observed below 673 K. Both In2O3 samples were found to be highly active and selective toward CO2 in methanol steam reforming over a broad temperature range (450 < T < 673 K). Selectivities of > 95% toward CO2 were usually observed, with at maximum 5% or less CO formed. No dependence of selectivity on either reaction temperature or oxidative/reductive pre-treatment was observed. No catalytic activity in both routes of the water-gas shift reaction as tested in the same temperature region where the catalysts exhibit high reforming activity and selectivity, could be observed. Therefore In2O3 based catalysts offer a broad range of temperature not influenced by unwanted CO formation via the inverse water-gas shift process. (c) 2008 Elsevier B.V. All rights reserved.