Metalloporphyrin modified glassy carbon electrodes for oxygen reduction: Investigation of local electrocatalytic activity

Ayodele O. Okunola ,  Xingxing Chen ,  Kathrin Eckhard ,  Michael Bron ,  Wolfgang Schuhmann 

Ruhr-Universität Bochum, Anal. Chem. - Elektroanalytik & Sensorik (ELAN), Universitätsstr. 150, Bochum 44780, Germany

Abstract

The development of suitable catalyst materials for oxygen reduction in the cathode half-cell reaction of PEM fuel cells has received tremendous attention in recent years. Metalloporphyrins supported on carbon blacks have proven to be potential candidates as suitable modification materials for the cathode with two and four electron reduction of oxygen to hydrogen peroxide and water respectively, as reported in literature. Heat treatment of these catalysts at temperatures between 400°C and 900°C has lead to enhanced stability. Basic investigations on those materials in principle use dip- or drop- coating techniques and sometimes combined with a heat treatment [1, 2]. Such modified surfaces have been applied extensively in the catalytic reduction of oxygen. An immediately observable limitation however is the possibility of quantifying effectively, the porphyrin-loading in the case of dip or drop coated materials and a drastic reduction in catalytic activity in the case of a heat-coated surface due to a destruction of the heat polymerized metalloporphyrin under high temperature conditions. In order to obtain quantifiable porphyrin loadings as modification materials, electro-polymerized metalloporphyrins of Fe and Mn using pulse potentials or cyclic votammetric deposition procedures have been established. Fundamental parameters such as ring substituents, porphyrin loading and their effects on activity and stability for oxygen reduction have also been investigated, with Fe-porphyrins showing better initial activity but Mn-porphyrins have shown better stability. A combination of two transition metalloporphyrins of Fe and Mn was also investigated. A further step was then taken to visualize the local electro-catalytic activity using scanning electrochemical microscopy (SECM). An estimation of the number of electrons involved in the oxygen electro reduction, to water or hydrogen peroxide was attempted, using the redox competition mode of scanning electrochemical microscopy (RC-SECM) [3]. Details of experimental procedures and results shall be discussed.

References

1. Jianying Qu, Yan Shen, Xiaohu Qu & Shaojun Dong. Chem. Commun., (2004), 34 - 35

2. Deryn Chu, Rongzhong Jiang. Solid State Ionics (2002), 148, 591 - 599

3. Kathrin Eckhard, Xinxing Chen, Florin Turcu & Wolfgang Schuhmann. Phys. Chem. Chem. Phys, (2006), 8, 5359 - 5365

Legal notice
  • Legal notice:

    Copyrighted materials, (c) Pielaszek Research, all rights reserved.
    The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced, stored in or introduced into a retrieval or caching system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording or otherwise), or for any purpose, without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
    In every case, proper references including Author(s) name(s) and URL of this webpage: http://science24.com/paper/12612 must be provided.

 

Related papers
  1. Hierarchical carbon nanotubes composite electrode – towards efficient enzymatic biocathodes based on direct electron transfer
  2. 3D bioarchitectures constructed on carbon cloth for the development of biofuel cells
  3. Electrodeposition of metalloporphyrines for the preparation of electrocatalytically active surfaces
  4. Design of the interface properties of self-assembled thiol/DNA monolayers for improved DNA detection assays.
  5. Impedimetric RNA assay – detection of the activity of a hairpin ribozyme
  6. Scanning electrochemical microscopy into the nanoscale
  7. Horse-radish peroxidase-modified 3D-hierarchical carbon nanotube electrode - characteristics and potential applications
  8. Laccase-redoxpolymer cathodes for biofuel cells. Evaluation using an electrochemical robotic system.
  9. Pyrolyzed polypyrrole-metal composites immobilized on glassy carbon for gas sensing and catalytic applications
  10. Visualisation of local catalyst activity towards oxygen reduction in hydrochloric acid solution with RC-SECM
  11. Determination of optimum imaging contrast in AC - SECM
  12. Scanning electrochemical microscopy - a tutorial lecture
  13. Electrochemical impedance spectroscopy (EIS) for detection of DNA hybridization in presence of intercalators
  14. Shearforce-based distance control in scanning electrochemical microscopy
  15. Surface Modification of Carbon Materials for Electrocatalysis: From Catalyst Development to the Hierarchical Build-up of Electrode Structures
  16. Mathematical tools for characterization of spatial variability of surface activity based on SECM images
  17. Visualisation of the effect on catalytic activity of increasing Pt agglomerate sizes using constant-distance mode SECM in a competition mode
  18. Reagentless biosensors based on mediator-modified electrodeposition hydrogels
  19. Microelectrochemistry. From Materials to Biological Applications

Presentation: Short communication at SMCBS'2007 International Workshop, by Ayodele O. Okunola
See On-line Journal of SMCBS'2007 International Workshop

Submitted: 2007-08-27 11:06
Revised:   2009-06-07 00:44
Google
 
Web science24.com
© 1998-2021 pielaszek research, all rights reserved Powered by the Conference Engine