One-step synthesis of Pt based electrocatalysts encapsulated by polyoxometalate for methanol oxidation

Methanol oxidation is a very important reaction in diret methanol fuel cells. Developing stable and efficient Pt-based catalysts with a convenient method has been on the stage recently. Herein, we employed a convenient one-pot method to synthesize Pt nanoparticles encapsulated by polyoxometalates (POMs) spreading on a few layers of graphene oxide with a nickel foam as a conductive substrate. Four kinds of samples with different Pt loadings were finally obtained by adjusting the H 2 PtCl 6 concentration, named as PPGN- n ( n = 1, 2, 3, 4). The microscopic structure of the sample was characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. It was proved that small-sized Pt nanoparticles with a diameter of ca. 2.47 nm spreaded on graphene oxide (GO) with the nickle foam support were successfully synthesized. The synthesized electrocatalysts exhibited higher electrocatalytic activities than commercial Pt/C for methanol oxidation in electrocatalytic tests. The mass activity of PPGN-1 of 250.6 mA mg −1 can be achieved. During the synthesis, POM was used as a bifunctional reagent; as a reductant for reducing chloroplatinic acid and a stabilizer for the regulation of the Pt nanoparticle size simultaneously. POM cooperated rapid synthesis of Pt nanoparticles can offer a new route for designing and synthesising electrocatalysts.