Performance, surface properties and structural transformation of a PdZn/Ceria catalyst were studied near stoichiometric H2O/CH3OH systematically over a range of aging conditions. Products CO and CO2 were found to lead to formation of carbonaceous compounds that negatively affect catalyst activity. Progressive formation of PdZn alloy and accumulation of carbonaceous compounds resulted in gradual improvements in reforming (H-2 or CO2) selectivity but with slow deactivation with time. Air purge during reactor startup and shutdown or oxidation at 400-600 degrees C was found effective to recover the lost catalyst activity. With over 2000h durability demonstrated at 400 degrees C. this catalyst is particularly suitable for washcoating on various metal surfaces to make compact reformers for fuel cell applications. (c) 2011 Elsevier B.V. All rights reserved.