Electrochemical Development of Ni-Cu Electrodes by Direct and Pulse Current Coating in Ethanol Electro-oxidation for DEFC

Abstract

The electrocatalytic property of electrode materials is the key for getting high cell current and low overvoltage of a fuel cell from fuels electro-oxidation. The bridge between laboratory scale fuel cell development and its fully commercialization is the development of inexpensive but energetic electrode materials. The catalytic actions of an electrode substrate are strongly influenced by the morphology and the grain fineness of the deposited materials. The present investigation aims at finding the effect of electrode deposition mode viz. direct current and pulse current coating, to produce an electrodeposited substrate that can deliver the highest current in a direct ethanol fuel cell. Nickel (Ni) is one of such non precious materials which has been produced through electro synthesis by both pulse current (PC) and direct current (DC) coating. It has been found that the morphology of the deposited is highly influenced by the current density, duty cycle, electrolyte chemistry and right selection of deposition potential on the cathodic polarization curve around the Tafel lines. Electrochemical characterization has been done by cyclic voltammetry (CV), chronoamperometry (CA) and potentiodynamic polarization (PD) studies. The substrate of the electrodeposited material has also been characterized by X-Ray Diffraction analysis (XRD), Energy Dispersive X-Ray Analysis (EDXA) and Scanning Electron Microscope (SEM). It has also been found that the electro synthesis by pulse current coating at pre-selected deposition potential, right at the end of Tafel region, at 40 ºC temperature and 150 second deposition time, gives the highest delivering current of ethanol fuel oxidation.Keywords: Direct ethanol fuel cell, inexpensive Ni-electrode, direct and pulse current coating, cyclic voltammetry, XRD, EDXA, SEM.* Corresponding author. E-mail address: sujitguchhait.chem@gmail.com, dr_spaul@yahoo.com S.K. Guchhait & S. Paul / Port. Electrochim. Acta 36 (2018) 293-307 294 IntroductionThe demand for energy is growing every day, due to fast urbanization, fulfillment of our daily needs and the progress of world economy. The energy demand has been mostly fulfilled by conventional energy resources, such as coal, natural gases, etc. However, the energy harvesting from this resources creates a lot of polluting gases, hazardous substances which have a very harmful impact on global environment, leading to health hazardous problems, not acceptable to the governments of developed and developing nations. So, the production of pollution free renewable energy at an economically viable price is a huge challenge to researchers and scientists. A fuel cell, operated with renewable fuels, is such a kind of alternative technology, to produce clean renewable energy [1]. In the fuel cell, fuel is electrochemically oxidized at the electro catalytic anode surface, knocking the electrons from the fuel, and transferring them in the form of current through the electrode and current collector to the external circuit. The energy conversion efficiency, b...

Designing Sustainable Ethanol Oxidation Catalysts: The Role of Graphene Oxide in NiCuGO Composite Material

“…Similar materials described in the literature have shown lower peak current densities, from 4.03 mA cm −2 observed for nanomaterial Ni20@Pd60Rh20 [62] through to 5.6 mA cm −2 for Ni-doped platinum [63]. As it is presented in Table 3 below, similar activity has been reported for electrodeposited NiCu material, with an ipA of 12.4 mA cm −2 [64]. Ni-Co composite deposited on reduced, nitrogen-doped GO has shown even higher activity, this being 64.2 mA cm −2 [65].…”