Abstract: Pt catalysts supported on γ-Al2O3 modified with Ce or Mg were prepared by impregnation with a H2PtCl6 aqueous solution and used in the hydrogen production by aqueous-phase reforming of ethylene glycol. Catalytic activity testing, N2 physical adsorption, CO chemical adsorption, X-ray diffraction (XRD), and temperature-programmed reduction (TPR) were employed to evaluate the activity, hydrogen selectivity, and physicochemical properties of the catalysts. The results indicate that Pt catalysts supported on γ-Al2O3 modified with Ce or Mg show higher activity than the Pt/γ-Al2O3 catalyst. At the temperature of 498 K and pressure of 2.58 MPa, the conversion of ethylene glycol is increased from 72.3% over Pt/γ-Al2O3 to 100% over Pt/(Ce)γ-Al2O3 or Pt/(Mg)γ-Al2O3, and the selectivity for hydrogen almost reaches 100%. The characteristic peaks attributed to CeO2, Mg-Al layer chemical component, and Mg-Al spinel have been observed besides the γ-Al2O3 peak in the XRD patterns of Pt/(Ce)γ-Al2O3 and Pt/(Mg)γ-Al2O3. The presence of Ce not only increases the dispersion of Pt on the surface of γ-Al2O3, but also improves the adsorption-cracking of ethylene glycol on Pt and water-gas shift reaction; while the presence of Mg neutralizes the acidity of γ-Al2O3, influences the dispersion of PtCl2-6, and inhibits the dehydration of ethylene glycol.

Key words: platinum, cerium, magnesium, alumina, supported catalyst, modification, ethylene glycol, aqueous-phase reforming, hydrogen production