Effects of metal cation doping in CeO2 support on catalytic methane steam reforming at low temperature in an electric field

Abstract

Catalytic methane steam reforming was conducted at low temperature using a Pd catalyst supported on Ce_1−xM_xO₂ (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-CeO₂ (Pd/Ce_0.9Al_0.1O₂) showed higher activity than Pd/CeO₂ with EF, although their activity was identical without EF. Thermogravimetry revealed a larger amount of H₂O adsorbed onto Pd/Al-CeO₂ than onto Pd/CeO₂, so Al doping to CeO₂ contributes to greater H₂O adsorption. Furthermore, electrochemical conduction measurements of Pd/Al-CeO₂ revealed a larger contribution of surface proton hopping than that for Pd/CeO₂. This promotes the surface proton conductivity and catalytic activity during EF application.