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Lookup NU author(s): Dr Maryam Bayati,
Emeritus Professor Keith Scott
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).
Nitrogen doped carbon materials are promising oxygen reduction reaction (ORR) catalysts which could potentially replace platinum. However, despite extensive studies, their active sites are still controversial and their impact on overall ORR remains obscure. Herein, we present a method for preparation of a single active site catalyst based on cycling an iron-inserted N-doped carbon catalyst in a wide potential window firstly in sulfuric acid and later in alkaline solution to study the contribution of the remaining one active group in overall activity. Following preparation of the metal-inserted N-doped carbon catalyst (MINC), its morphology was characterized using X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and the electro-catalytic behavior was investigated by employing linear sweep voltammetry (LSV) using a rotating ring disk electrode (RRDE). XPS revealed that graphitic nitrogen was the only remaining active nitrogen-containing group after elimination the pyridinic and pyrrolic groups and also iron nano-materials removal confirmed from auger peak of Fe LMMa and poisoning reaction with cyanide. The C1 s XPS region data showed an increase in the oxygen reduction intermediate C-OH peak, after the reaction, which indicates electrocatalytic activity of the graphitic carbon. Electrochemical studies revealed no significant changes in limiting current, a small increase in H2O2 production and 47 mV shift in half wave potential for degraded catalyst which is in line with previous theoretical calculations. (C) 2016 Elsevier Ltd. All rights reserved.
Author(s): Bayati M, Scott K
Publication type: Article
Publication status: Published
Journal: Electrochimica Acta
Print publication date: 20/09/2016
Online publication date: 26/06/2016
Acceptance date: 17/06/2016
Date deposited: 04/11/2016
ISSN (print): 0013-4686
ISSN (electronic): 1873-3859
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