Synthesis And Characterization Of Graphene Supported Pt Based Binary Catalyst For Direct Methanol Fuel Cell

Direct methanol fuel cell(DMFC) has drawn wide attention for its simple structure, high energy density and environmental friendliness, but the current low catalytic efficiency of and poor stability Pt-based catalysts still restrict the commercialization of DMFC, and therefore how to design and synthesize efficient catalyst is one of the key factors to improve battery performance. In this paper, two new Pt-based binary anode catalyst were prepared based on graphene material and the catalytic acitiviey and stability of catalysts were further investigated in detail.First, with graphene as a carrier and homemade Ni2 P as cocatalyst, a new Pt-Ni2P/G catalyst was synthesized by a microwave-assisted method, and Pt/G catalyst was also prepared for comparasion. The structure and morphology were tested by XRD, TEM, XPS and other physical methods, and the results show that particle size of Pt-Ni2P/G catalyst becomes smaller with better dispersion. There might exist electron transfer between Ni2 P, Pt and graphene, altering the structure of the electron cloud of Pt. The electrocatalytic activity and stability were characterized by cyclic voltammetry, CO stripping and chronoamperometry. The results show that Pt-Ni2P/G has larger electrochemically active area, the peak current density of methanol oxidation reaches 21.84 m A cm-2, higher than that of P/G(16.28 m A cm-2), indicating Pt-Ni2P/G has a higher catalytic activity and superior anti-poisoning ability.To investigate the influence of different second conpoment on catalytic performace, Mn O2 was introduced as the cocatalyst and graphene as the supporting material, and the as prepared catalyst was represented by Pt-Mn O2/r GO(PMG). To further enhance the stability of catalyst, a new Pt-Mn O2/r GO-L catalyst(PMGL) was then prepared using a low-carbon sugar derivative L- ascorbic acid(C6H8O6) as the carbon source in situ carbonized on Mn O2 surface, enhancing the interaction between Pt, Mn O2 and graphene. In the stability analysis, the three stable current densities are 2.97 m A cm-2, 1.36 m A cm-2 and 0.84 m A cm-2, respectively. In the single cell performance test, PMGL catalyst owns a maximum power density of 26.31 m W cm-2, followed by the PMG’s 21.11 m W cm-2, and a minimum 16.13 m W cm-2 of PG. These results reflect not only the synergistic effect between Mn O2 and Pt, but also the anchor of nanoparticles and stability enhancement by L-ascorbic acid during the in-situ carbonization process. The new graphene-based binary catalysts prepared herein have great research and practical value.