A simple, environmentally benign, and cost‐effective approach is described to prepare graphene via electrochemical exfoliation of graphite rod from spent batteries. PdNi was deposited on electrochemically exfoliated graphene materials with the electrocatalyst synthesized using a borohydride‐facilitated reduction. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) analysis confirmed the exfoliation of graphite from used batteries and deposition of PdNi on electrochemically exfoliated graphenebased material. Cyclic voltammetry results show that the electrocatalytic activity towards ethanol oxidation of PdNi on electrochemically exfoliated graphene oxide (EGO) exfoliated from graphite of used battery has improved compared to carbon black as a support material.
Catalysts in fuel cells are normally platinum based because platinum exhibits high electrocatalytic activity towards ethanol oxidation in acidic medium. However, bulk Pt is expensive and rare in nature. To reduce the consumption of Pt, a support material or matrix is needed to disperse Pt on its surface as micro- or nanoparticles with potential application as anode material in direct ethanol fuel cells (DEFCs). In this study, a composite material consisting of platinum particles dispersed on reduced graphene oxide/poly(3,4-ethylenedioxythiophene) (RGO/PEDOT) support was electrochemically prepared for ethanol oxidation in sulfuric acid electrolyte. PEDOT, a conductive polymer, was potentiodynamically polymerized from the corresponding monomer, 0.10 M EDOT in 0.10 M HClO4electrolyte. The PEDOT-modified electrode was used as a substrate for exfoliated graphene oxide (EGO) which was prepared by electrochemical exfoliation of graphite from carbon rod of spent batteries and subsequently reduced to form RGO. The Pt/RGO/PEDOT composite gave the highest electrocatalytic activity with an anodic current density of 2688.7 mA·cm−2at E = 0.70 V (versus Ag/AgCl) towards ethanol oxidation compared to bare Pt electrode and other composites. Scanning electron microscopy (SEM) revealed the surface morphology of the hybrid composites while energy dispersive X-ray (EDX) confirmed the presence of all the elements for the Pt/RGO/PEDOT composite.
This study aims to utilize pulse electrodeposition to synthesize tin/palladium/exfoliated graphene oxide (Sn/Pd/EGO) catalyst composite as anode material for ethanol oxidation reaction (EOR) which finds significant application in Direct Ethanol Fuel Cell (DEFC) application. The electrocatalytic activity of the prepared catalysts towards ethanol oxidation was evaluated using cyclic voltammetry in 1 M ethanol in 0.1 M NaOH. Cyclic voltammetry showed that the addition of Sn to Pd improved the catalytic activity of Pd towards EOR in alkaline solution. The bimetallic Sn/Pd catalyst on glassy carbon electrode (Sn/Pd/GCE) showed a higher catalytic activity with a peak current density of 28.1 mA cm--2 , compared to Pd/GCE (23.39 mA cm -2 ). The electrocatalytic activity of bimetallic Sn/Pd catalyst further improved when EGO was used as a support (Sn/Pd/EGO) with a peak current density of 36.7 mA cm -2 . Atomic force microscopy revealed that the catalysts were deposited on the edges of the graphene sheets forming bright clusters with dark fringes on the middle of the structure. X-ray photoelectron spectroscopy confirmed the presence of Pd and Sn metals and their oxides. This study demonstrates that pulse electrodeposition could offer a much simpler and faster approach in the development of high performance catalysts for EOR.
Direct ethanol fuel cell can serve as alternative to fossil fuels because it is renewable and environmentally-friendly with a high energy conversion efficiency and low pollutant emission. In line with this, an effective anode electrocatalyst should be present which will facilitate the oxidation of the fuel (e.g. ethanol). This study aims to synthesize and characterize a graphenesupported Pd/Ni/Sn electrocatalyst for ethanol oxidation. Modified Hummer's method was used to produce graphene oxide. The Pd/Ni/Sn supported on reduced graphene oxide (RGO) was synthesized using borohydride-facilitated reduction method. Optimization of the product showed that 12 h of reduction time as well as sequential addition of Sn, Ni, and then Pd to the RGO support with atomic ratio kept at 3:2:2 (Pd, Ni, and Sn, respectively) generated the highest maximum current density of 12.64 mAcm -2 at a scan rate of 50 mVs -1 . AFM analysis of the synthesized graphene as well as the Pd/Ni/Sn/RGO catalyst composite indicated graphenelike structures having a thickness of 6-8 nm as well as bright particles that could be indicative of metallic particles with an average particle size of 30-40 nm. The synthesized Pd/Ni/Sn/ RGO electrocatalyst proved to be effective in facilitating ethanol oxidation in alkaline medium.
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