WO3/CeO2/YSZ nanocomposite as a potential catalyst for methanol reforming

A WO3/CeO2/YSZ nanocomposite material [W/Zr nominal atomic ratio = 0.025, Ce/Zr nominal atomic ratio = 0.020] was prepared by wet impregnation and characterized by means of X-ray photoelectron and diffuse reflectance infrared Fourier transform spectroscopic techniques, X-ray diffraction and thermal analysis. Both tungsten and cerium oxides are significantly reduced at the interface with YSZ:Ce(III), in particular, seems to be the prevailing species. The interaction of the WO3/CeO2/YSZ nanopowder with pyridine and CO2 allowed to investigate the acidic/basic sites. Weak contributions at 1602, 1625 and 1647 cm(-1) suggest the presence of Lewis and Bronsted acidic sites, whereas basic sites are not evidenced by the interaction with carbon dioxide. The presence of tungsten oxide causes the decrement of the acidic/basic sites, as indicated by the comparison with the results obtained on the CeO2/YSZ support. Consistently, the interaction with methanol is mainly molecular. The oxidation of methanol was investigated both in the absence and in the presence of water. In the last case carbon dioxide starts forming from room temperature. (c) 2005 Elsevier B.V. All rights reserved.