Formation of Pt-NiO/rGO triphasic junction with significantly enhanced electrocatalytic activity for methanol oxidation

Abstract

Pt-based nanocomposites such as Pt- metal oxide framework have been widely used as electro catalysts for direct methanol fuel cell (DMFC) due to their significant catalytic activity and stability. In this study, Pt-NiO encapsulated with reduced graphene oxide (rGO) nanosheet is prepared by making a thin film of GO over deposited Pt-NiO on Indium tin oxide support, followed by facile electrochemical reduction technique. As-synthesized materials are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The electrocatalytic performance is investigated by cyclic voltammetry (CV), chronoamperometry and impedance spectroscopy. These results indicate that Pt-NiO/rGO ternary phase catalyst junction exhibits significant CV peak current density (669 mA mg−1 of Pt) which is 2.9 and 1.7 times higher than that of fabricated Pt-NiO and commercial Pt(10 mass% )-XC72 respectively. The electrode also possesses excellent stable catalytic activity than Pt-NiO. The charge transfer conductance of Pt-NiO based electrode is improved 17 times and the electrochemical surface area is increased by ca. 2 times by incorporation of overhead rGO nanosheet. These results imply that Pt-NiO/rGO nanocomposite could be a better electrocatalyst for DMFCs application.