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 Ce0.9Cu0.1OY 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 Ce0.9Cu0.1OY 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 Ce0.9Cu0.1OY-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 Ce0.9Cu0.1OY-cp and Ce0.9Cu0.1OY-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 Ce0.9Cu0.1OY-cc from the oxidative steam reforming of methanol at 240 °C. However, the catalysts prepared by coprecipitation and the deposition–precipitation method showed methanol conversion lower than 30% at 240 °C, and less than 60% even at 360 °C. The high catalytic activity of Ce0.9Cu0.1OY-cc is mainly related to the formation of solid solution and the improved redox properties.