Design and synthesis of Pd decorated rGO-MoSe2 2D hybrid network as high performance electrocatalyst toward methanol electrooxidation

Abstract

Direct methanol fuel cells (DMFCs) have attracted profound interest for development of future green energy sources, which are being powered by methanol as a fuel. The critical problem identified with DMFCs is the deactivation of electrocatalysts resulting from the adsorption of CO during methanol oxidation. In this work, we have employed a new synthetic approach by a green microwave method for the synthesis of hybrid Pd-MoSe2-rGO and Pd-rGO nanocomposites. The synthesized electrocatalysts were successfully characterized by XRD, which is used to identify the crystalline phases, FESEM and TEM analyses for morphological features, XPS for analyzing the elements constituting the composites surface and Raman spectroscopy for the analysis of molecular structural bonding. Electrocatalytic activity was explored by cyclic voltammetry (CV), chronoamperometry (CA) and CO stripping techniques. Electroactive surface area (EASA) of the developed hybrid electrocatalyst Pd-MoSe2-rGO (51.81 m2 g−1Pd) was more than 3.4 times superior activity than that of Pd-rGO catalyst (15.30 m2 g−1Pd). It was observed that the synthesized catalyst with 3D cross-linked hybrid network facilitated even distribution of metal nanoparticles and exhibited nearly four times enhanced electrocatalytic activity (1935 mA mg−1Pd) towards methanol oxidation reaction (MOR) in alkaline medium, compared to Pd-rGO (546 mA mg−1Pd). Under constant applied potential investigations, catalytic activity of Pd-MoSe2-rGO was nearly 50 times higher than that of Pd-rGO at the end of about 1 h. The ease of the availability of more active sites and high tolerance against CO poisoning resulted by the insertion of MoSe2 led to enhanced catalytic activity of Pd-MoSe2-rGO towards MOR. It is conceived that this synthetic strategy by employing a combination of 2D materials like MoSe2, graphene and Pd nanoparticles together as building blocks for 3D hybrid network led to efficient electrocatalysts with high surface area and long-term stability towards methanol oxidation. This synthetic strategy exhibits a promising prospect to develop durable and stable electrocatalyst for DMFC applications.