Selective production of hydrogen from partial oxidation of methanol over supported silver catalysts prepared by method of redox coprecipitation

Supported silver catalysts showed good activity for hydrogen production from partial oxidation of methanol (POM) at a low temperature of 160 degrees C. Ag/CeO2-ZnO catalysts, prepared by the method of redox coprecipitation, displayed distinguished hydrogen selectivity (S-H2) and methanol conversion. In preparation of the catalysts, Ag+ ions were found reduced into metal clusters by Ce3+ ions. X-ray diffraction study revealed that the active silver crystallites were dispersed amorphously on the catalysts. Thermal characterization of temperature programmed hydrogen reduction and temperature programmed hydrogen desorption further suggested that CeO2 and ZnO played different roles in the high S-H2 over Ag/CeO2-ZnO. Promoter CeO2 served as a spillover sink to collect hydrogen dissociated on silver crystallites while ZnO acted as a porthole for a fast desorption of hydrogen from the catalyst. These two oxides corporately raised the high S-H2 over Ag/CeO2-ZnO catalysts. (C) 2009 Published by Elsevier B.V.