Preparation, Characterization and Catalystic Activity of the Copper-based Catalyst for Water-gas Shift Reaction

Abstract: In this thesis, supported and unsupported copper-based shift catalysts were prepared by different methods. Effects of the loading amount of the active components, supporters, temperature of calcination and the promoter on activity were investigated in the water-gas shift reaction. Chemical and physical properties of catalysts were also characterized by means of XRD, TEM, SEM, BET and so on.(1). Copper, zinc and aluminum hydroxides sol were prepared by sol method and then supported on MgAl2O4 spinel. Effects of the loading amount of the component, ratio of copper and zinc and the temperature of calcination were investigated. The best activity was gained when the amount of the components were 25%, 25% and 12.8%. CO conversion reached the equilibrium at 350℃and 80% at 250℃.(2). Copper nanoparticle was prepared by precipitation at high temperature with an average diameter of 10 nm, which supported on the different supporters. It was found that Alumina supporter was the best one. Catalytic activity was the volcanic type with increasing amount of copper oxide. CO conversion reached the nearly equilibrium at 200℃and 72% at 160℃when the loading of copper oxide was 40%, which displayed the better activity at low temperature.(3). Unsupported catalysts were obtained by the way of the hydrothermal and homogeneous precipitation accomplished by urea hydrolysis. The average diameter of the catalyst was 12 nm. The specific surface area, pore volum and average pore width were 120m<sup>2</sup>/g, 0.23cm<sup>3</sup>/g and 7nm. The component and temperature of calcination had an obvious on the catalytic activity. CO conversion reached the equilibrium at 200℃and 50% at 140℃under the condition of the molar ratio was Cu:Zn:Al=3:3:2.5 and calcination at 450oC for 2h. The equilibrium temperature was decreased by 20oC with the 3% addition of CeO<sub>2</sub>. This catalyst also had good stability and cyclic shut-down and start-up performance.
Key words: copper-zinc based catalyst; WGS; supported; low temperature;

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