Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619389
Title: Computational studies of mono- and bimetallic nanoclusters for potential polymer electrolyte fuel cell applications
Author: Jennings, Paul Christopher
ISNI:       0000 0004 5358 0539
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 2014
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Abstract:
A problem with the Polymer Electrolyte Fuel Cell (PEFC) is the expensive platinum (Pt) electrocatalyst. This thesis aims to investigate alloying of Pt with cheaper metals that not only reduce the overall cost but also alter the electronic properties to improve reaction kinetics. A Genetic Algorithm (GA) coupled with Density Functional Theory (DFT) approach has been used to perform structural searches on small Pt clusters doped with early transition metals (M). It is found that varying spin can have significant effects on the minimum energy structures of pure Pt clusters, while doping with early transition metals leads to spin quenching. DFT studies have been performed to predict potential Pt-based alloy nanoparticles that will result in weaker Pt–O interactions. This is achieved by investigating nanoalloys that lead to filling of the Pt d-band. Early transition metals are found to be promising, where donation of electron density from M to Pt results in additional filling of the Pt d-band. The surfaces of pure Pt clusters are found to distort, facilitating fast oxygen dissociation. It is found that the strong Pt-M interactions, which lead to filling of the d-band, can lead to Pt clusters becoming more structurally rigid, which inhibits oxygen dissociation. A search has been performed to find the best compromise for a system that retains flexibility of the Pt surface, to allow fast dissociation while also allowing M to Pt electron donation, leading to filling of the Pt d-band.
Supervisor: Not available Sponsor: Engineering and Physical Sciences Research Council (EPSRC)
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.619389  DOI: Not available
Keywords: TP Chemical technology
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