New approaches to the preparation of highly efficient chromium-containing oxide catalysts for the water gas shift reaction

• Published in: Kinetics and catalysis 2009-11, Vol.50 (6), p.837-850
• Main Authors: Khassin, A. A., Minyukova, T. P., Demeshkina, M. P., Baronskaya, N. A., Plyasova, L. M., Kustova, G. N., Zaikovskii, V. I., Yurieva, T. M.
• Format: Article
• Language: English
• Subjects: Catalysis; Chemistry; Chemistry and Materials Science; Physical Chemistry
• ISSN: 0023-1584; 1608-3210
• DOI: 10.1134/S002315840906007X

It was found experimentally that the solutions of Cr 3+ nitrate and the nitrates of other metals that are the constituents of Cr-containing catalysts can be prepared by dissolving a corresponding metal (for example, cast iron and electrolytic copper) in a solution of chromic anhydride and nitric acid to reach the quantitative reduction of Cr 6+ without the formation of nitrogen oxides. Analogously, the oxidation of Fe 2+ cations to Fe 3+ coupled with the reduction of hexavalent chromium can be performed. The precipitation of Fe 3+ , Cr 3+ , and Cu 2+ ions at a ratio of Fe: Cr = 9 and a concentration of Cu 2+ to 20 at % can result in the formation of a partially hydrated oxide with the hydrohematite structure—a dispersed and highly defective oxide structure with a high specific surface area more than 300 m 2 /g and a higher thermal stability, as compared with the goethite phase (α-FeOOH). The dehydration of hydrohematite occurred at a noticeable rate at temperatures higher than 400°C. Hydrohematite promoted with copper cations exhibited high activity below 400°C; this can decrease the starting temperature of the adiabatic high-temperature WGSR to 300°C or below.