Altmetric

Mechanistic Insights into the Oxygen Reduction Reactionon Metal–N–C Electrocatalysts under Fuel Cell Conditions

Title: Mechanistic Insights into the Oxygen Reduction Reactionon Metal–N–C Electrocatalysts under Fuel Cell Conditions
Authors: Lopes, T
Kucernak, A
Malko, D
Ticianelli, EA
Item Type: Journal Article
Abstract: Three different transition metal-C-N catalysts are tested under a range of fuel cell conditions. It is found that common features of the polarisation curve can be explained by a change in electrocatalytic mechanism. Utilising a simple model to quantify the change in mechanisms, iR free results of the fuel cell experiments are fit and found to be represented by a common set of parameters. The change in mechanism is assumed to be a switch from four electron reduction of oxygen to water to a two electron reduction to hydrogen peroxide followed by disproportionation of the hydrogen peroxide to water and oxygen. The data is used to estimate a mass specific exchange current density towards the ORR in the range 10-11-10-13 A g-1 depending on the catalyst. For the reduction of oxygen to hydrogen peroxide, the mass specific exchange current density is estimated to be in the range 10-2-10-3 A g-1. Utilising the electrokinetic model, it is shown how the mass transport losses can be extracted from the polarisation curve. For all three catalyst layers studied, these mass transport losses reach about 100mV at a current density of 1 A cm-2. Finally a discussion of the performance and site density requirements of the non-precious metal catalysts are provided, and it is estimated that the activity towards the ORR needs to be increased by an order of magnitude, and the site density by two/three orders of magnitude in order to compete with platinum as an ORR electrocatalyst.
Issue Date: 6-Sep-2016
Date of Acceptance: 8-Aug-2016
URI: http://hdl.handle.net/10044/1/38849
DOI: https://dx.doi.org/10.1002/celc.201600354
ISSN: 2196-0216
Publisher: Wiley
Start Page: 1580
End Page: 1590
Journal / Book Title: ChemElectroChem
Volume: 3
Issue: 10
Copyright Statement: © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.This is an open access article under the terms of the Creative Commons At-tribution License, which permits use, distribution and reproduction in anymedium, provided the original work is properly cited.
Sponsor/Funder: Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (EPSRC)
Funder's Grant Number: EP/J016454/1
EP/K503381/1
Publication Status: Published
Appears in Collections:Chemistry
Faculty of Natural Sciences



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Creative Commonsx