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Tungsten based electrocatalysts as non-noble alternatives to common platinum based fuel cell catalysts

Tungsten based electrocatalysts as non-noble alternatives to common platinum based fuel cell catalysts
Tungsten based electrocatalysts as non-noble alternatives to common platinum based fuel cell catalysts
Today fuel cells are far from being common place in the commercial market, primarily due to their high cost. The cost of such a system is largely determined by the platinum based catalysts used at both the anode and cathode of the fuel cell. If a non-noble fuel cell electrocatalyst could be used at either of these electrodes, the cost of a fuel cell system would be drastically reduced. Highthroughput physical vapour deposition and the modification of single crystal surfaces, has been used to synthesise candidate non-noble electrocatalysts which were then screened to determine their activity.

Amorphous tungsten carbide thin films were shown to be catalytically active towards both the hydrogen evolution reaction (HER) and the hydrogen oxidation reaction (HOR). The constituent elements were seen to be less active than the alloys. These results are consistent with the literature where it has also been seen that WC is active, with W2C showing poorer activity.1,2 The trend in current density with respect to alloy composition confirms the results in the literature, with the highest activity seen at compositions corresponding to the WC phase, and a local minima in activity seen at compositions corresponding
to the W2C phase.

Metastable and amorphous intertransition metal alloys of WCu are shown to catalyse both the HER and the HOR. The constituent metals again exhibit poor activity. The results are consistent with ab initio calculations predicting HER activity for Cu overlayers on W, with the detected changes of the density of states (DOS) at the Fermi level associated with alloy formation.3 Two maxima in the HER activity are observed as a function of composition. This activity is associated with a metastable phase at W20Cu80 and a second at W50Cu50. The alloy at 50 at% also shows a maximum in the HOR activity, whereas the phase at W20Cu80 is not HOR active. The W20Cu80 phase is found to beoxygen covered at the HOR potential, explaining its inactivity. These results highlight the potentials of developing non-noble metal alloy catalysts for hydrogen fuel cells.
Blake, John
16f8eb29-e4eb-4f4b-8da7-2a431fce9caf
Blake, John
16f8eb29-e4eb-4f4b-8da7-2a431fce9caf
Hayden, Brian
aea74f68-2264-4487-9d84-5b12ddbbb331

Blake, John (2013) Tungsten based electrocatalysts as non-noble alternatives to common platinum based fuel cell catalysts. University of Southampton, School of Chemistry, Doctoral Thesis, 294pp.

Record type: Thesis (Doctoral)

Abstract

Today fuel cells are far from being common place in the commercial market, primarily due to their high cost. The cost of such a system is largely determined by the platinum based catalysts used at both the anode and cathode of the fuel cell. If a non-noble fuel cell electrocatalyst could be used at either of these electrodes, the cost of a fuel cell system would be drastically reduced. Highthroughput physical vapour deposition and the modification of single crystal surfaces, has been used to synthesise candidate non-noble electrocatalysts which were then screened to determine their activity.

Amorphous tungsten carbide thin films were shown to be catalytically active towards both the hydrogen evolution reaction (HER) and the hydrogen oxidation reaction (HOR). The constituent elements were seen to be less active than the alloys. These results are consistent with the literature where it has also been seen that WC is active, with W2C showing poorer activity.1,2 The trend in current density with respect to alloy composition confirms the results in the literature, with the highest activity seen at compositions corresponding to the WC phase, and a local minima in activity seen at compositions corresponding
to the W2C phase.

Metastable and amorphous intertransition metal alloys of WCu are shown to catalyse both the HER and the HOR. The constituent metals again exhibit poor activity. The results are consistent with ab initio calculations predicting HER activity for Cu overlayers on W, with the detected changes of the density of states (DOS) at the Fermi level associated with alloy formation.3 Two maxima in the HER activity are observed as a function of composition. This activity is associated with a metastable phase at W20Cu80 and a second at W50Cu50. The alloy at 50 at% also shows a maximum in the HOR activity, whereas the phase at W20Cu80 is not HOR active. The W20Cu80 phase is found to beoxygen covered at the HOR potential, explaining its inactivity. These results highlight the potentials of developing non-noble metal alloy catalysts for hydrogen fuel cells.

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Published date: 31 March 2013
Organisations: University of Southampton, Chemistry

Identifiers

Local EPrints ID: 360211
URI: https://eprints.soton.ac.uk/id/eprint/360211
PURE UUID: 836c5a7d-a353-4123-bf56-74a5ad42380c
ORCID for Brian Hayden: ORCID iD orcid.org/0000-0002-7762-1812

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Date deposited: 06 Jan 2014 13:51
Last modified: 06 Jun 2018 13:16

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Contributors

Author: John Blake
Thesis advisor: Brian Hayden ORCID iD

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