Effects of metal cation doping in CeO 2 support on catalytic methane steam reforming at low temperature in an electric field.

Catalytic methane steam reforming was conducted at low temperature using a Pd catalyst supported on Ce 1- x M x O 2 ( x = 0 or 0.1, M = Ca, Ba, La, Y or Al) oxides with or without an electric field (EF). The effects of the catalyst support on catalytic activity and surface proton hopping were investigated. Results show that Pd/Al-CeO 2 (Pd/Ce 0.9 Al 0.1 O 2 ) showed higher activity than Pd/CeO 2 with EF, although their activity was identical without EF. Thermogravimetry revealed a larger amount of H 2 O adsorbed onto Pd/Al-CeO 2 than onto Pd/CeO 2 , so Al doping to CeO 2 contributes to greater H 2 O adsorption. Furthermore, electrochemical conduction measurements of Pd/Al-CeO 2 revealed a larger contribution of surface proton hopping than that for Pd/CeO 2 . This promotes the surface proton conductivity and catalytic activity during EF application.