Al2O3改性CuO/Fe2O3催化剂水煤气变换反应性能

Performance of Al2O3-Modified CuO/Fe2O3 Catalysts in the Water-Gas Shift Reaction

The water-gas shift reaction (WGSR) has been carried out over CuO/Fe₂O₃ catalysts modified by different loadings of Al₂O₃ (0%-15% (w)), prepared by a stepwise co-precipitation method. Composite mixture CuFe₂O₄ was produced, and the crystalline size, redox property, and surface metallic Cu dispersion were manipulated. The appropriate introduction of Al₂O₃ can promote the phase transition of spinel CuFe₂O₄ from tetragonal to cubic, inhibit aggregation of Cu-crystallite, improve Cu dispersion, and increase the amount of weak basic sites, as confirmed using powder X-ray diffraction (XRD), Raman spectroscopy, N₂ physisorption, N₂O decomposition, and temperature-programmed desorption of carbon dioxide (CO₂-TPD) techniques. In addition, a temperature-programmed reduction of hydrogen (H₂-TPR) technique was used to investigate the reducibility of the modified CuO/Fe₂O₃ catalysts. It was found that the Al₂O₃-doping plays an important role in increasing the hydrogen consumption of the copper species, and decreasing reduction temperature. This means that the Al₂O₃ can promote a synergistic interaction between the copper and iron species in the CuO/Fe₂O₃ catalysts. Overall, the Al₂O₃-modified catalyst (10%(w)) has a smaller Cu particle size, better Cu dispersion, greater reducibility, and larger amount of weak basic sites, resulting in a much higher initial catalytic activity and better thermal stability.