Uncovering the Electroactivity of Novel sp2 Carbon Materials through Quantitative High Resolution Visualisation

Lead Research Organisation: University of Warwick
Department Name: Chemistry

Abstract

Electrochemistry is a key enabling science of the 21st century, underpinning important topics and technologies such as energy (conversion and storage), catalysis/electrocatalysis, and sensing (chemical and biochemical). All of these applications demand new electrode materials which can outperform existing technologies and offer environmental benefits. In this context, carbon is very attractive: while (precious) metals have to be mined and processed (with high energy costs), carbon materials can be grown from carbon-containing gases quickly, cheaply and efficiently. The recent emergence of new forms of carbon, in particular, graphene (a one-atom-thick planar sheet of sp2 carbon atoms in a honeycomb arrangement) and single-walled carbon nanotubes (SWNTs), which may be viewed as graphene rolled into tubes with a diameter on the nanometer (one-billionth of a meter) scale, presents an exciting opportunity for electrochemistry. SWNTs have displayed astonishing properties for electrochemical (current-sensing) detection, and it is anticipated that graphene will offer even better prospects for electroanalysis and electrocatalysis. Both materials constitute particularly interesting platforms for the assembly of catalysts (metal, semiconductor, enzymes, cells, etc.) and could find application as transparent electrodes in solar cells. These applications, and many others, require that the fundamental aspects of charge transfer (current flow) between carbon electrodes and molecules in solution is understood. This poses a major experimental challenge. While having long-range order, sp2 carbon materials (graphene, graphite and SWNTs) possess surface features (defects and/or steps); the extent to which these, rather than the basal surface, contribute to the overall activity is a major open question and a matter of considerable debate and importance.This proposal will take on the challenge of elucidating, for the first time, the true activity of sp2 carbon materials through the development and application of the highest spatial-resolution electrochemical imaging techniques ever. These techniques will be able to measure electrochemical activity across a surface on a scale which has not been possible hitherto. The techniques are based on the 'scanned probe' concept in which a nanoscale-probe is moved across a surface; in this case, it will measure the electrochemical activity in minute detail and relate it to the underlying surface properties (structural and electrical), via the use of complementary microscopy methods. We expect to obtain definitive proof of the origin of the activity of related sp2 carbon materials and to determine whether charge transfer is driven only at defects. Answering this question for a wide range of important electrochemical processes is vital for the advancement of the field and will reveal the best strategies for the future development of sp2 carbon-based electrochemical technologies.The uncertainty surrounding the active sites on solid electrodes is widespread and of a general nature, and we fully expect the techniques proposed to be applied extensively in electrochemistry and materials science, where one seeks to understand surface reactivity. Downstream applications of the techniques could include understanding corrosion and supported fuel cell catalysts. Ultimately, the techniques could find considerable use in the life sciences, including probing living systems and organelles, where one would be able to measure chemical fluxes on a minute scale. This proposal is therefore of fundamental importance to the basic understanding of new materials, as well as more broadly to electrochemistry and surface reactivity. It will lead to new methods of sensing and electrochemical transformations, and will provide scientists with novel high resolution techniques with far-reaching multidisciplinary impact.

Planned Impact

This project, which involves major technique development, the fabrication and characterisation of novel carbon electrode materials, and fundamental studies of electron transfer has the potential to deliver major impact on several fronts: (i) novel instruments for nanoscale (electro)chemical imaging will be created which could be used in many areas of research beyond that in the project; (ii) new formats for (electrochemical) sensors, based on the improved understanding of carbon materials, resulting from the programme, are expected. Beneficiaries of (i) include a wide range of industrial sectors. Since its inception in 1992, the Warwick Electrochemistry and Interfaces Group, led by the applicants, has had a strong ethos in ensuring that fundamental discoveries (funded by EPSRC and other agencies) are taken up in industrial programmes. The applicants currently have 7 funded contracts with 6 companies on a wide range of projects, including sensor development, understanding new surface-active formulations, high resolution imaging, fuel cell catalysts, crystal growth and dental processes, with two additional companies as project partners in a sensor development project. In total, the applicants have worked with 12 companies on > 25 funded projects in the past 12 years alone. These projects have utilised science, techniques and know-how developed in EPSRC programmes. We have found colleagues in industry to be receptive to our fundamental technique developments and fully expect the techniques that we will develop in this project to have major applications in other areas. Potential applications include understanding corrosion, electrocatalysts, surface processes - such as dissolution/crystallisation - and life sciences problems (probing cells and organelles). As the project develops we will ensure that commercial end users are aware of our developments, via our network of existing and past collaborators, and new external contacts that we are making through the EPSRC Warwick Centre for Analytical Science, which serves as a hub for analytical instrumentation development. Furthermore, our involvement in the Advantage West Midlands Science City project gives us access to a dedicated business development manager. We typically have approximately 12 - 15 industrial visitors per year to our laboratories and a small number of industrial secondments. These will serve as additional mechanisms to ensure that end-users are aware of, and can make use of, our research. During the course of the project we will also consider ways to license our instrumentation developments. At the end of the project, for example, we would have a unique instrument capable of SECM, SICM and SNCM imaging, which could be attractive to industrial and academic users. Industrialists will be able to take part in the workshop we will run. The fundamental understanding gained of the various carbon materials will be beneficial in designing formats for new electrochemical sensors that would greatly enhance the detection limits compared to conventional electrodes. In this area, we would seek to protect IP and know-how, consider licensing or the formation of a spin-out company and enter into discussions with sensor companies in the water quality and diagnostics markets about adopting new carbon materials for sensor applications. Again, we have a track record of ensuring that we deliver impact in this regard: our recent work on carbon (SWNTs and diamond) electrodes has resulted in 5 patent applications and the commisioning of a business development report to identify how to take this forward. Imaging, nanoscience and new forms of carbon are highly visual and potentially exciting topics to convey to school children. Warwick Chemistry has an active outreach progarmme (engaging with 3,500 children in the past year alone) and we plan to devise activities based on the project for use in outreach/engagement activities.

Publications

10 25 50

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Güell AG (2012) Quantitative nanoscale visualization of heterogeneous electron transfer rates in 2D carbon nanotube networks. in Proceedings of the National Academy of Sciences of the United States of America

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Kirkman PM (2014) Spatial and temporal control of the diazonium modification of sp2 carbon surfaces. in Journal of the American Chemical Society

 
Title Artist in Residence 
Description We are using images from the project, along with other images in Warwick Chemistry, as artistic inspiration in a follow up project funded by the Leverhulme Trust, which has brought Mary Courtney to the department as an artist in residence. 
Type Of Art Artwork 
Year Produced 2016 
Impact Artwork is being produced and their will be an audio visual installation sometime in 2016, along with many other works. 
 
Description Our work has radically changed fundamental understanding of electrochemical processes, challenging and overturning dogma, and providing an entirely new perspective on the electrochemical behaviour of carbon materials, including nanotubes, graphene, graphite and conducting boron doped diamond (BDD). Carbon materials are among the most studied in electrochemistry and attract considerable fundamental and applied interest (100's of publications per year and applications in energy storage/conversion technologies and sensors). Before our work, the dominant (text book) view - from conventional measurements over 2 decades - was that the basal surfaces (or sidewalls) of graphite and carbon nanotubes, were effectively inert for electrochemistry; step edges and defects were required. In the case of polycrystalline diamond, grain boundaries were considered to be the active sites. We have shown that these models are either questionable or simply incorrect for a wide range of reactions. This has been possible because we have invented new high resolution electrochemical imaging techniques that can investigate the activity of different components of electrode surfaces (e.g. terraces, sidewalls, facets, defects, step edges) individually and unambiguously. Furthermore, and importantly, we have advocated correlative-microscopy approaches, where electrochemical microscopy data are combined with information from other forms of microscopy and spectroscopy in the same area of the surface, to produce highly detailed quantitative pictures of electrode activity. Field-changing advances include:

(i) Showing that outer sphere electron transfer, and other electrochemical processes - from proton-electron coupled transfer to metal electrodeposition, occur readily at the basal surface of graphite, i.e. it has significant electrochemical activity.
(ii) Rationalising the complex interplay in electrochemistry at graphene of the number of graphene layers and the arrangement of those layers, edges, electronic structure and redox couple.
(iii) Introducing a novel platform to relate the nanoscale electrochemistry of single-walled carbon nanotubes (SWNTs) to the electronic characteristics, size and quality of the nanotube.
(iv) Highlighting the significant intrinsic electrocatalytic properties (oxygen reduction reaction) of defect-free SWNTS, and showing that defects further enhance the activity for complex multistep reactions.
(v) Implementing innovative methods for patterning carbon surfaces at the nanoscale, and showing that chemical functionalisation does not require defects or occur preferentially at step edges.
(vi) Defining structural controls for the electroactivity of polycrystalline BDD surfaces, for a wide range of reactions, leading to the rational design of diamond electrode materials.
Exploitation Route The importance of the advances made is several-fold. First, our work provides a completely new framework on the activity of carbon electrode materials, which will direct future use in sensing and energy applications (among others). Second, from a fundamental viewpoint, our work has highlighted that while the density of electronic states (and electronic structure) of some carbon materials (e.g. graphene and semi-conducting carbon nanotubes) may be important in determining electron transfer kinetics, graphite itself behaves like a metal for many electrode reactions, resolving an issue which has been long-debated in electrochemistry. Finally, our body of work illuminates perfectly the importance of unconventional microscopic approaches to test the findings of conventional macroscopic measurements and the microscopic models that are derived from them.

Thus, the new knowledge we have provided on carbon electrode materials will be hugely valuable for the future use of these materials, while the technqiues we have invented will be applicable across a wide spectrum of the physical and life sciences (from corrosion and catalysis to the functioning of living cells, amopng many other applications).
Sectors Agriculture, Food and Drink,Chemicals,Construction,Electronics,Energy,Healthcare,Pharmaceuticals and Medical Biotechnology,Other

URL http://www.warwick.ac.uk/electrochemistry
 
Description Catalysis Hub (EPSRC)
Amount £80,000 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 01/2017 
End 12/2017
 
Description Marie Curie Fellowship
Amount € 180,000 (EUR)
Funding ID POLYMAP 329953 
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 07/2013 
End 06/2015
 
Description Marie Curie Fellowship
Amount € 180,000 (EUR)
Funding ID NEIL H2020 702048 
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 09/2016 
End 08/2018
 
Description Marie Curie Fellowship
Amount € 180,000 (EUR)
Funding ID FUNICIS FP7 626158 
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 06/2014 
End 05/2016
 
Description ARC Center of Excellence in Electromaterials Science 
Organisation University of Wollongong
Country Australia 
Sector Academic/University 
PI Contribution We are one of 7 international partners for this major (ca. AU$25M) ARC Centre that brings togther leading groups in Australia in electromaterials.
Collaborator Contribution We provide access to state of the art instrumentation for nanoscale electrochemical imaging. I have a joint PhD student with Monash University, and host short term visits from Autralian researchers as well as making visits to Australian universities.
Impact Three papers so far, a joint PhD student and collaborative visits.
Start Year 2014
 
Description Collaboration with Leiden University 
Organisation Leiden University
Country Netherlands 
Sector Academic/University 
PI Contribution A joint effort, using techniques established in EPSRC research to understand electrocatalysts. Led to two papers in JACS, one in Anal Chem and a major review in Angew Chem Int Ed
Collaborator Contribution We hosted PhD students from Leiden to work on our state of the art equipment.
Impact 2 papers in JACS, one in Angew Chem Int Ed and one in Anal Chem.
Start Year 2012
 
Description Collaboration with University of Burgos (Spain) 
Organisation University of Burgos
PI Contribution Access to our innovative instrumentation
Collaborator Contribution PhD student
Impact Publication in Analytical Chemistry.
Start Year 2014
 
Description Collaboration with University of Oviedo (Spain) 
Organisation University of Oviedo
Country Spain 
Sector Academic/University 
PI Contribution Hosted PhD student from Oviedo to work on understanding screen printed carbon electrodes with our innovative techniques
Collaborator Contribution PhD student
Impact Paper in preparation
Start Year 2015
 
Description Corrosion and steel research 
Organisation Tata Steel Europe
Country United Kingdom 
Sector Private 
PI Contribution A collaboration with Tata Steel Europe and Prof. Barbara Shollock (WMG) to apply our state of the art electrochemical imaging techniques to corrosion processes.
Collaborator Contribution EPSRC iCASE award and top up and access and expertise in high resolution structural characterisation techniques.
Impact The project is in its early stages and we expect to make a significant impact on corrosion research.
Start Year 2015
 
Description Crystallisation and dissolution of pharmaceutical crystals 
Organisation AstraZeneca
Country United Kingdom 
Sector Private 
PI Contribution Use our innovative methods as new probes of crystallisation and dissolution of pharmaceutical crystals.
Collaborator Contribution Part funding for PhD student and short term postdoc.
Impact M. Adobes-Vidal, F. M. Maddar, D. Momotenko, L. P. Hughes, S. A. C. Wren, L. N. Poloni, M. D. Ward and P. R. Unwin, Face-Discriminating Dissolution Kinetics of Furosemide Single Crystals: In Situ Three-Dimensional Multi-Microscopy and Modeling, Cryst. Growth Des., 2016, 16, 4421- 4429. Further papers to be submitted.
Start Year 2013
 
Description Dental and related research 
Organisation Unilever
Department Unilever UK R&D Centre Port Sunlight
Country United Kingdom 
Sector Private 
PI Contribution We extended our state of the art techniques to address interfacial processes in teeth, hair and household care.
Collaborator Contribution Funding for postdocs and support for students. Expertise and facilities at Port Sunlight
Impact Several papers and vital science to support the launch of a new product, and information to further understanding.
Start Year 2011
 
Description Electrochemical and flux probes of interfacial polymerization reactions 
Organisation Syngenta International AG
Department Syngenta Crop Protection
Country United Kingdom 
Sector Private 
PI Contribution We are using our state of teh art imaging techniques as a new way to understand interfacial polymerisation.
Collaborator Contribution iCASE award and top, plus access to facilities at Syngenta.
Impact E. E. Oseland, Z. J Ayres, A. Basile, D. M. Haddleton, P. Wilson and P. R. Unwin, Surface Patterning of Polyacrylamide Gel using Scanning Electrochemical Cell Microscopy (SECCM), Chem. Commun., 2016, 52, 9929 - 9932. E. E. Oseland, A. Rea, M. I. de Heer, J. D. Fowler and P. R. Unwin, Interfacial kinetics in a model emulsion polymerisation system using microelectrochemical measurements at expanding droplets (MEMED) and time lapse microscopy, J. Colloid Interfac. Sci, 2017, 490, 703 - 709.
Start Year 2012
 
Description iCASE Award on corrosion 
Organisation TATA Steel
Country India 
Sector Private 
PI Contribution Project to commence in Oct 2019
Collaborator Contribution Project to commence in Oct 2019
Impact To commence
Start Year 2019
 
Title Scanning Electrochemical Microscopy 
Description Intermittent contact scanning electrochemical microscopy as a way to intelligently position and move an electrochemical probe. 
IP Reference US20150059027A1 and US20130032495A1 (2 patents) 
Protection Patent granted
Year Protection Granted
Licensed Yes
Impact The invention has been incorporated into Uniscan/Biologic Scanned electrochemical probe workstation and a number of instruments with this invention have been sold worldwide. A further instrument is in development.
 
Title Warwick Electrochemical Scanning Probe Microscopy (WEC-SPM) software 
Description This software, written in LabVIEW, enables our innovative electrochemical imaging instruments to be realised (instrument control and data acquisition). 
Type Of Technology Software 
Year Produced 2013 
Impact The software has been taken up by 3 leading academic groups in the USA and a group in Germany is also looking to adopt the software. 
 
Description Electrochemical imaging lecture 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Lecture to pupils at Aylesbury Grammar School
Year(s) Of Engagement Activity 2014
 
Description London International Science Youth Festival 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Schools
Results and Impact We host a one day visit from young people who attend the LISYF, with activities centred on electrochemistry, imaging, energy and nanoscience. This is a whole day event in which I, the postdoc and PhD student on the grant run different activities, along with other students from my group. We are a popular venue with approx. 25-30 young scientists from all over the world visiting us annually.
Year(s) Of Engagement Activity Pre-2006,2006,2007,2008,
 
Description Outreach activity (Coventry Special Learning Unit) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact A 6-week project with the Grange Special Learning Unit for pupils who have been excluded, or at risk of being excluded, from mainstream education. The pupils engaged weekly with me and my team to do research spanning fieldwork to analysis with our techniques. The project was reported in the local paper and also the attention of senior managers at the University.
Year(s) Of Engagement Activity 2012
URL http://www2.warwick.ac.uk/fac/sci/chemistry/research/unwin/electrochemistry/about_us/outreach/the_gr...
 
Description PLacements for local year 11, 12 and 13 pupils 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact I host a few pupils every year to carry out research projects in my group. This has led to several changing their choice of subject to study at University to Chemistry.
Year(s) Of Engagement Activity 2012,2013,2014,2015,2016
 
Description Research projects for year 12 students 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Pupils from President Kennedy School carried out research projects on electrochemistry and imaging and reported their results in a seminar attended by approx 40 people.
Year(s) Of Engagement Activity 2014
URL http://www2.warwick.ac.uk/fac/sci/chemistry/research/unwin/electrochemistry/about_us/news/?newsItem=...
 
Description VerseReaction 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Presented images form this research as part of an event at the Earlsdon Festival, communicating science through art. This was one of a number of such events held during 2016 and the project further used images for video installations and films presented at the University of Warwick and online.
Year(s) Of Engagement Activity 2016