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Heterojunction α-Fe2O3/ZnO Films with Enhanced Photocatalytic Properties Grown by Aerosol-Assisted Chemical Vapour Deposition |
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| Authors: | Dr Arreerat Jiamprasertboon Dr Andreas Kafizas Michael Sachs Dr Min Ling Abdullah M Alotaibi Dr Yao Lu Prof Theeranun Siritanon Prof Ivan P Parkin Prof Claire J Carmalt |
| Institution: | 1. School of Chemistry, Institute of Science, Suranaree University of Technology, 111 University Avenue, Muang, Nakhon Ratchasima, 30000 Thailand
Material Chemistry Centre, Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ UK;2. Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ UK The Grantham Institute, Imperial College London, South Kensington, London, SW7 2AZ UK;3. The Grantham Institute, Imperial College London, South Kensington, London, SW7 2AZ UK;4. Material Chemistry Centre, Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ UK;5. Department of Mechanical Engineering, University College London, London, WC1E 7JE UK;6. School of Chemistry, Institute of Science, Suranaree University of Technology, 111 University Avenue, Muang, Nakhon Ratchasima, 30000 Thailand |
| Abstract: | Type I heterojunction films of α-Fe2O3/ZnO are reported here as a non-titania based photocatalyst, which shows remarkable enhancement in the photocatalytic properties towards stearic acid degradation under UVA-light exposure (λ=365 nm), with a quantum efficiency of ξ=4.42±1.54×10?4 molecules degraded/photon, which was about 16 times greater than that of α-Fe2O3, and 2.5 times greater than that of ZnO. Considering that the degradation of stearic acid requires 104 electron transfers for each molecule, this represents an overall quantum efficiency of 4.60 % for the α-Fe2O3/ZnO heterojunction. Time-resolved transient absorption spectroscopy (TAS) revealed the charge-carrier behaviour responsible for this increase in activity. Photogenerated electrons, formed in the ZnO layer, were transferred into the α-Fe2O3 layer on the pre-μs timescale, which reduced electron–hole recombination. This increased the lifetime of photogenerated holes formed in ZnO, which oxidise stearic acid. The heterojunction α-Fe2O3/ZnO films grown herein show potential environmental applications as coatings for self-cleaning windows and surfaces. |
| Keywords: | aerosol-assisted CVD films hematite heterojunctions photocatalysis |