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Observation of visible light activated photocatalytic degradation of stearic acid on thin films of tantalum oxynitride synthesized by aerosol assisted chemical vapour deposition

Observation of visible light activated photocatalytic degradation of stearic acid on thin films of tantalum oxynitride synthesized by aerosol assisted chemical vapour deposition
Observation of visible light activated photocatalytic degradation of stearic acid on thin films of tantalum oxynitride synthesized by aerosol assisted chemical vapour deposition
UV activated photocatalysts deposited using chemical vapour deposition have found commercial success as self-cleaning coatings. However, only limited work has been conducted on the use of the more recently discovered visible light activated photocatalysis for this application. Tantalum oxynitride is an established visible light photocatalyst, and in this paper we have investigated the ability of thin films of tantalum oxynitride to photocatalytically degrade a model organic pollutant, stearic acid, and therefore assess the coatings potential for self-cleaning applications. Thin films of tantalum oxide were formed using aerosol assisted chemical vapour deposition (AACVD) of tantalum ethoxide, and then converted into tantalum oxynitride through ammonolysis at temperatures between 550 °C and 750 °C. Investigation of the films using XRD, UV-vis spectroscopy and XAFS identify that amorphous tantalum oxynitride is formed during the ammonolysis, with complete conversion to TaON under conditions of 700 °C for 24 hours. The self-cleaning ability of this film was assessed using stearic acid as the model pollutant, with a degradation rate of 2.5(2) × 1013 molecules min-1 cm-2 when exposed to a 5-sun solar simulator, equipped with a UV cut-off filter. We therefore conclude that tantalum oxynitride thin films are able to act as self-cleaning coatings through visible light photocatalysis and that films of tantalum oxynitride can be synthesized using a scalable chemical vapour deposition route.
0300-9246
10619-10627
Cosham, Samuel D.
a2dd18d3-e232-44b6-baa0-3ba0e2aba2be
Celorrio, Veronica
5ebb7fb5-a74c-4872-9795-5830dc915d0b
Kulak, Alexander N.
7dc57b4f-aae0-42a4-ae15-fd50ab6521c2
Hyett, Geoffrey
4f292fc9-2198-4b18-99b9-3c74e7dfed8d
Cosham, Samuel D.
a2dd18d3-e232-44b6-baa0-3ba0e2aba2be
Celorrio, Veronica
5ebb7fb5-a74c-4872-9795-5830dc915d0b
Kulak, Alexander N.
7dc57b4f-aae0-42a4-ae15-fd50ab6521c2
Hyett, Geoffrey
4f292fc9-2198-4b18-99b9-3c74e7dfed8d

Cosham, Samuel D., Celorrio, Veronica, Kulak, Alexander N. and Hyett, Geoffrey (2019) Observation of visible light activated photocatalytic degradation of stearic acid on thin films of tantalum oxynitride synthesized by aerosol assisted chemical vapour deposition. Dalton Transactions, 48 (28), 10619-10627. (doi:10.1039/C8DT04638G).

Record type: Article

Abstract

UV activated photocatalysts deposited using chemical vapour deposition have found commercial success as self-cleaning coatings. However, only limited work has been conducted on the use of the more recently discovered visible light activated photocatalysis for this application. Tantalum oxynitride is an established visible light photocatalyst, and in this paper we have investigated the ability of thin films of tantalum oxynitride to photocatalytically degrade a model organic pollutant, stearic acid, and therefore assess the coatings potential for self-cleaning applications. Thin films of tantalum oxide were formed using aerosol assisted chemical vapour deposition (AACVD) of tantalum ethoxide, and then converted into tantalum oxynitride through ammonolysis at temperatures between 550 °C and 750 °C. Investigation of the films using XRD, UV-vis spectroscopy and XAFS identify that amorphous tantalum oxynitride is formed during the ammonolysis, with complete conversion to TaON under conditions of 700 °C for 24 hours. The self-cleaning ability of this film was assessed using stearic acid as the model pollutant, with a degradation rate of 2.5(2) × 1013 molecules min-1 cm-2 when exposed to a 5-sun solar simulator, equipped with a UV cut-off filter. We therefore conclude that tantalum oxynitride thin films are able to act as self-cleaning coatings through visible light photocatalysis and that films of tantalum oxynitride can be synthesized using a scalable chemical vapour deposition route.

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Hyett_TaON_photocatalysis_V3 - Accepted Manuscript
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Accepted/In Press date: 17 June 2019
e-pub ahead of print date: 17 June 2019
Published date: 28 July 2019

Identifiers

Local EPrints ID: 431910
URI: http://eprints.soton.ac.uk/id/eprint/431910
ISSN: 0300-9246
PURE UUID: 3088a3cd-c41f-4d75-b7c4-d442fc354e22
ORCID for Geoffrey Hyett: ORCID iD orcid.org/0000-0001-9302-9723

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Date deposited: 21 Jun 2019 16:30
Last modified: 16 Mar 2024 07:57

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Contributors

Author: Samuel D. Cosham
Author: Veronica Celorrio
Author: Alexander N. Kulak
Author: Geoffrey Hyett ORCID iD

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