Porous SnO2 hexagonal prism-attached Pd/rGO with enhanced electrocatalytic activity for methanol oxidation

Abstract

Porous SnO₂ hexagonal prisms, as a new promoter, were attached to Pd-based systems held by a reduced graphene oxide (rGO) support (Pd–SnO₂/rGO) for the catalysis of the electrooxidation reaction of methanol. Cyclic voltammetry (CV) tests revealed that the electrocatalytic activity and stability were substantially improved by SnO₂ with a special morphology. The specific activity (SA, j_k, area) and mass activity (MA, j_k, area) of Pd–SnO₂/rGO were enhanced 1.31 and 3.3 times those of the Pd/rGO catalyst, respectively. Moreover, the CO-tolerance was also remarkably enhanced due to the presence of SnO₂. It is believed that higher surface areas, more active sites, which are offered by the porous architecture of SnO₂, as well as the synergetic effect between all components contribute to the improvement of the catalytic activities of the Pd–SnO₂/rGO catalysts. Cost savings and the CO-poisoning obstacle being surmounted, which are the two main probing directions for elevating the overall performance of direct methanol fuel cells, makes the as-prepared Pd–SnO₂/rGO a promising electrocatalyst.