Nitrogen-Doped Graphene Supported PtSn Nanoparticles Composite Catalyst For Ethanol Electrocatalytic Oxidation

As promising power sources for portable devices, direct methanol fuelcells (DMFC) have attracted great attention on account of the high energydensity, reduction of fossil fuel consumption, and low operatingtemperature. Electrocatalyst mainly focus on platinum. In order toimprove the CO tolerance, the Ru，Ni，Au，Pb，Sn and other transitionelement was introduced as the second metal in the form of binary andternary alloy. Due to low cost, Sn as a second metal was common ascatalyst has great research value. Graphene, a two-dimensionalnanomaterial with a single or a few sheet of carbon atoms, has receivedsignificant attention owing to its fascinating properties, such as extremelyhigh specific surface area, exceptional electrical conductivity, andsuperior thermal/chemical stability, which makes it a promising catalystsupport for fuel-cell applications. Graphene-supported platinum was widely used as the anode catalyst for ethanol oxidation reaction (EOR).However, Pt is a costly and limited resource, posing problems for itspractical application in Pt-based fuel cells. Thus, strategies to improveelectrocatalytic activity with minimum loading of Pt, while maximizingthe utility of the loaded Pt, have been developed to solve this problem.Graphene doped nitrogen is an effective method to increase the utilizationrate of Pt. In this work, we further prepared the nitrogen doped graphenesupporting PtSn Electrocatalyst for ethanol oxidation reaction.Modified Hummers method was employed to synthesize grapheneoxide, and nitrogen doped graphene was prepared by using hydrazinehydrate to reduce graphene oxide, on which Pt-Sn nanoparticles wasdeposited. X-ray diffraction (XRD), X-ray photoelectron spectroscopy(XPS) and Transmission electron microscopy (TEM) were applied tocharacterize the surface composition, morphology and microstructure,while cyclic voltammetry (CV) and chronoamperometry (CA) werecarried out to evaluate the electrocatalytic ethanol oxidation activity anddurability of the obtained Pt-Sn/G-N catalysts.The experimental results indicate that: the nitrogen-doped grapheneexhibits signifcant chemical and structural changes, which subsequentlymodulate the nucleation and growth behavior of supported platinumnanopaticles, resulting in more uniform nanoparticles with smallernanoparticle size and higher the radio of Pt and Sn; the introduction of Sn and the existence of nitrogen functional groups collaboratively obstacledthe agglomeration of metal nanoparticles. The activity of electriccatalyticoxidation of the Pt-Sn/G-N catalysts was higher, and the stability ofPt-Sn/G-N catalysts is much better.