Novel catalytic heterostructure for fuel cells based on functional block-copolymers mediated self-assembly

Research area: Polymer science, nanomaterials and electrocatalysis
Supervisors: Prof Namita Roy Choudhury, Prof Naba Dutta, Dr A Hill (CSIRO Process Science and Eingineering) and Prof S Holdcroft (Simon Fraser University, Canada)

Aims: The overall aim of the project is to develop a family of harmonized, catalytically active heterostructure from noble metal nanoparticle-loaded carbon nanotubes (CNTs) using a combination of electrospinning and block copolymer self assembly (SA) approach.

Description: The synthesis of nanoparticles with controlled shape, size and structure has been one of the major focuses of recent research in nanotechnology [1-5]. Recently, highly attractive bottom-up fabrication schemes for synthesizing nanoparticles by template method using natural (such as DNA, bacterial surface layer proteins, ferritin, viruses, etc.) or artificial nano-architectures have been reported [5].

Amongst many templates, the meso-phase separated block copolymers [BCP] offer distinctive advantages over other materials [5]. The potential advantage of using phase separated BCP to create controlled growth of desired nanoparticles derives from the diversity of their architectural possibilities, ease of handling, low cost, and unique tunability of the organization, size, shape, periodicity, and binding of nanoparticles to the self assembled nano-domains [5-8]. However, in most applications to achieve the novel and unique properties that are not found in the individual particles/components, precise organization of the nanoparticles into well-defined assemblies/patterns is essential [1,5-9].

Among the noble group metals, platinum is best known for its catalytic activity in various chemical and electrochemical reactions including energy conversion devices such as fuel cells (eg. PEMFC, DMFC). The current platinum (Pt), Pt-alloy based catalytic systems used in PEMFC electrodes are plagued with problems such as carbon monoxide (CO) poisoning, sluggish oxygen reduction reaction (ORR) kinetics, 'Pt hiding', degradation of activity over electrochemical cycling, and cost. This has prompted intense research on developing high performance catalytic system with high dispersion of the catalytic particles and improved transport phenomena and stability.

The major focus of this research is to develop nanoscale heterostructure involving platinum (Pt) and Pt-alloy nanoparticles as electrocatalyst, and multiwall carbon nanotubes (MWCNT) as support and molecular wiring material. Both carbon nanotubes (CNTs) and (Pt) and Pt-alloy nanoparticles exhibit many advantageous properties and their potential applications are wide and varied.

The hybrid self-assembled structures involving them present versatile molecular constructs with an array of unique electronic and surface properties, which have significant potential impact on emerging fields such as energy supply, storage and production (fuel cells, batteries, solar cells), information technology (nano-optics, electronics), sensors and biomedical applications [1-4]. In this project we will strategically design and synthesise novel proton conducting functional block copolymers and precisely tune their self-organization process under different controlled environment to use them as nanoreactor.

A fundamental understanding will be developed between the structure and function of such novel heterostructure, and finally the work will demonstrate the outstanding catalytic utilization and effectiveness of the developed catalyst in PEMFC. In depth understanding of the interdependence of the catalytic properties on the type of the nanoparticles, its size, size distribution, morphology and its interaction with the support and stabilizing ionomer will be developed. The high surface area and the 3D network like structure of the heterostructure will enhance the catalytic performance at decreased level of metal concentration. The research has the potential to pioneer the development of novel catalyst support for the energy conversion devices.

References
1. S. Mayavan, N. Roy Choudhury and N.K. Dutta, Advanced Materials, 20, 2008.
2. N.K. Dutta, S. Mayavan, N. Roy Choudhury, NSTI, Nanotech-2008, Hynes Convention Centre, Boston, June 1-5.
3. Z.Chen, M. Waje, W. Li, Y. Yan Angew. Chem. Int. Ed., , 46 (2007) 4060.
4. T. Maiyalagan, B. Viswanathan , U.V. Varadaraju, Electrochemistry Communications 7(2005) 905.
5. N.K.Dutta and N. Roy Choudhury, Self-assembly and supramolecular assembly in nanophase separated polymers and thin films, in Functional Nanostructures:Processing, Characterization and Applications, ed. S. Seal, p220-304, Springer, 2008.
6. R. E.Cohen Curr. Opin. Solid State Mater. Sci., 4(6)(2000) 587.
7. J. I Abes, R. E Cohen,.C. A. Ross, Chem. Mater., 15(5)(2003) 1125.
8. T.Ishida, and M.Haruta, Angew. Chem. Int. Ed., 46(2007) 7154.
9. T. J. McDonald, D. Svedruzic,Y-H. Kim, J. L. Blackburn, S.B. Zhang, P.W. King, M. J. Heben, Nanoletters, 7(2007) 3528.

Collaboration: This is a collaborative project and the research methodology will primarily cover investigations carried out at The Wark and CSIRO, Victoria and Simon Fraser University, Canada).

Funding: A grant application to the Australian Research Council is currently being assessed. If successful, this grant will support two Wark fully funded scholarship.

International students should also apply for an International Postgraduate Research Scholarship (IPRS) and a UniSA President's Scholarship (UPS). Australian students should also apply for an Australian Postgraduate Award (APA) and a UniSA Australian Postgraduate Research Award (USAPRA). Project maintenance costs will be met from internal funding.

Areas of study and research

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