Oxidizing- and sintering- resistant PdZn@ZnO catalyst concerning methanol steam reforming for on-board hydrogen production for fuel cell vehicles

Abstract

For proton exchange membrane fuel cells (PEMFCs) powered vehicles using on-board H2 production by methanol steam reforming (SRM), how to enhance the anti-oxidation and anti-sintering abilities of SRM catalysts are two challenges. Herein, to address the two challenges, a PdZn@ZnO catalyst has been synthesized by in-situ transformation of Pd@ZnO core-shell structure under thermal treatment and H2 reduction, which is a facile and green method. The PdZn@ZnO catalyst exhibited an excellent anti-oxidation ability without obvious change in catalytic activity before and after oxidation treatment. Density functional theory calculations revealed that the abundant PdZn/ZnO interface sites of PdZn@ZnO catalyst could suppress O2 dissociation and subsequent oxidation of the PdZn catalyst. In addition, ZnO shell of PdZn@ZnO prevented the encapsulated PdZn alloys from sintering, resulting in its superior stability to those of the reported catalysts. The PdZn@ZnO catalyst showed great potential for the on-board production of hydrogen for PEMFC-powered vehicles.