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Pre-Reduction of Au/Iron Oxide Catalyst for Low-Temperature Water-Gas Shift Reaction Below 150 °C
Department of Chemical Engineering, Graduate School of Engineering, Kyoto University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
Research and Education Center of Carbon Resources, Kyushu University, Kasuga 816-8580, Japan
* Author to whom correspondence should be addressed.
Received: 6 October 2011; in revised form: 14 November 2011 / Accepted: 29 November 2011 / Published: 9 December 2011
Abstract: Low-temperature water-gas shift reaction (WGS) using gold catalyst is expected to be an attractive technique to realize an efficient on-site hydrogen production process. In this paper, Au/Fe3O4 catalysts for promoting the WGS below 150 °C were developed by a preliminary reduction of Au/iron oxide (Fe3+) catalyst utilizing high reactivity of Au nano-particles. The reduction was conducted under a CO, H2, or CO/H2O stream at either 140 or 200 °C, and the effect of reduction conditions on the characteristics of the Au/Fe3O4 catalyst and on the catalytic activity in WGS at 80 °C was investigated. The reaction progress during the pre-reduction treatment was qualitatively analyzed, and it was found that the iron oxide in Au/Fe2O3 calcined at 200 °C was easily reduced to Fe3O4 phase in all reduction conditions. The reduction conditions affected the characteristics of both Au and iron oxide, but all of the reduced catalysts had small Fe3O4 particles of less than 20 nm with Au particles on the surface. The surface area and content of cationic Au were high in the order of CO, H2, CO/H2O, and 140, 200 °C. In the WGS test at 80 °C using the developed catalysts, the activities of the catalysts pre-reduced by CO at 140 or 200 °C and by H2 at 140 °C were very high with 100% CO conversion even at such a low temperature. These results indicated that factors such as higher surface area, crystallized Fe3O4, and cationic Au content contributed to the catalytic activity.
Keywords: water-gas shift; gold catalyst; iron oxide; pretreatment; reduction; activation
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Kudo, S.; Maki, T.; Fukuda, T.; Mae, K. Pre-Reduction of Au/Iron Oxide Catalyst for Low-Temperature Water-Gas Shift Reaction Below 150 °C. Catalysts 2011, 1, 175-190.
Kudo S, Maki T, Fukuda T, Mae K. Pre-Reduction of Au/Iron Oxide Catalyst for Low-Temperature Water-Gas Shift Reaction Below 150 °C. Catalysts. 2011; 1(1):175-190.
Kudo, Shinji; Maki, Taisuke; Fukuda, Takashi; Mae, Kazuhiro. 2011. "Pre-Reduction of Au/Iron Oxide Catalyst for Low-Temperature Water-Gas Shift Reaction Below 150 °C." Catalysts 1, no. 1: 175-190.