A newly-designed sandwich-structured graphene–Pt–graphene catalyst with improved electrocatalytic performance for fuel cells

Abstract

A novel sandwich-structured graphene–Pt–graphene (G–P–G) catalyst has been synthesized by a convenient approach. The obtained G–P–G catalyst has been characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy, and electrochemical measurements. Structural characterization shows that the G–P–G catalyst has a well-defined sandwich-like morphology. The results of electrochemical measurements indicate that the G–P–G exhibits 1.27 times higher activity for methanol electrooxidation than that of the Pt/graphene catalyst. Importantly, the results of the accelerated potential cycling test demonstrate that the G–P–G catalyst possesses 1.7 times higher stability than that of Pt/graphene. The significantly enhanced electrochemical performance is ascribed to its unique sandwich-like structure. Pt nanoparticles are anchored between the two adjacent graphene sheets, substantially enhancing the metal–support interaction, and graphene could act as a “mesh bag” to prevent the Pt species from leaking into the electrolyte, so its stability has considerably been enhanced. The effect of composited graphene amount on the stability of the hybrid has also been systematically studied. The stability of the catalyst increases with the increase of the introduced GO amount and the G–P–G₅₀ shows optimized electrocatalytic performance. These findings suggest that the sandwich-structured G–P–G catalyst holds tremendous promise for fuel cells.