Visualisation of local catalyst activity towards oxygen reduction in hydrochloric acid solution with RC-SECM

Artjom Maljusch ,  Kathrin Eckhard ,  Michael Bron ,  Wolfgang Schuhmann 

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

Abstract

In order to analyse local catalytic activity with high spatial resolution a transient redox competition mode of scanning electrochemical microscopy (RC-SECM) has been developed and described [1]. In a bi-potentiostatic experiment the SECM tip is positioned in close proximity to the surface of sample. Both electrodes are polarised to consume oxygen. If the SECM tip is close enough to an active catalyst, it will start to compete with the sample for the very same analyte in the gap between them. This leads to a noticeable tip current decrease over active sites of the sample. In order to avoid complete O2 depletion a potential pulse profile is used for electrochemically oxygen generation prior to the competition detection. Highly dispersed electro-deposited spots of gold and platinum on glassy carbon as catalysts for reduction of molecular oxygen were investigated and successfully visualised in chloride free phosphate buffer (pH = 7) using RC-SECM [1]. However, visualisation of local catalytic activity of catalysts for oxygen reduction in chloride containing solutions by high pH has not been reported yet. 


Figure 1. Local catalyst activity visualised by means of  RC-SECM   

In chloride containing solutions the oxygen generation pulse in RC-SECM leads to chloride oxidation to chlorine, which is very corrosive and can affect the activity of the catalysts. In this contribution, cyclic voltammetry and chronoamperometry were used for investigation of chloride oxidation process in hydrochloric acid solution. To overcome chlorine evolution during the lateral activity measurements the pulsprofile  has  to  be  adapted. With this modified  RC-SECM  the local catalytic activity  of  catalysts in a hydrochloric acid solution has been studied and successfully visualised (Fig.1). A specifically designed cell allows the investigation of powder catalysts. Development of this approach and first results are presented.



[1] K. Eckhard, X. Chen, F. Turcu, W. Schuhmann, PCCP 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/12661 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. Determination of optimum imaging contrast in AC - SECM
  11. Scanning electrochemical microscopy - a tutorial lecture
  12. Electrochemical impedance spectroscopy (EIS) for detection of DNA hybridization in presence of intercalators
  13. Shearforce-based distance control in scanning electrochemical microscopy
  14. Metalloporphyrin modified glassy carbon electrodes for oxygen reduction: Investigation of local electrocatalytic activity
  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: Poster at SMCBS'2007 International Workshop, by Artjom Maljusch
See On-line Journal of SMCBS'2007 International Workshop

Submitted: 2007-09-02 19:15
Revised:   2009-06-07 00:44
Google
 
Web science24.com
© 1998-2021 pielaszek research, all rights reserved Powered by the Conference Engine