Oxidative steam reforming of methanol on Ce0.9Cu0.1OY catalysts prepared by deposition-precipitation, coprecipitation, and complexation-combustion methods

The production of hydrogen from oxidative steam reforming of methanol has been tested for Ce0.9Cu0.(1)Ogamma catalysts. The catalysts were prepared by deposition-precipitation (dp), coprecipitation (cp), and complexation-combustion (cc) methods. These catalysts were characterized using BET, TEM, X-ray diffraction (XRD), and Raman spectroscopy. A solid solution was formed in the Ce0.9Cu0.(1)Ogamma prepared by complexation-combustion. The incorporation of Cu atoms into CeO2 lattice leads to an increase of oxygen vacancy. XPS results indicated that the Cu+ is the main Cu species for the Ce(0.9)Cu(0.1)Ogamma-cc sample and the synergistic function between Cu2+/Cu+ and Ce4+/Ce3+ occurred in the redox cycle, which is the reason for lower reduction temperatures and improved redox properties as shown in TPR profiles. In the case of the Ce(0.9)Cu(0.1)Ogamma-cp and Ce(0.9)Cu(0.1)Ogamma-dp samples, most CuO dispersed on the CeO2; the poor interaction between CuO and CeO2 does not affect redox properties of CeO2. Methanol conversions higher than 85% with 90% hydrogen yield were obtained for Ce(0.9)Cu(0.1)Ogamma-cc from the oxidative steam reforming of methanol at 240degreesC. However, the catalysts prepared by coprecipitation and the deposition-precipitation method showed methanol conversion lower than 30% at 240degreesC, and less than 60% even at 360degreesC. The high catalytic activity of Ce(0.1)Cu(0.1)Ogamma-cc is mainly related to the formation of solid solution and the improved redox properties. (C) 2004 Published by Elsevier Inc.