Speaker
Description
Arnold Mutubuki[1], Nyasha Joseph Suliali[2] and Johannes Reinhardt Botha[1]
1 Physics Department, Nelson Mandela University, P.O. Box 77000, Gqeberha 6031, South Africa
2 School of Physics, Engineering and Technology University of York, Heslington, York YO10 5DD, United Kingdom
Corresponding author email address: s226046524@mandela.ac.za
Photoelectrochemical water splitting (PECWS) for hydrogen evolution through solar exploitation is a potential alternative way of harnessing energy [1]. $TiO_{2}$ is a well-known photocatalyst with exceptionally reliable chemical properties [1]. Highly ordered $TiO_{2}$ nanotube arrays prepared by electrochemical anodization have widely been used as photocatalysts due to their unique structure, large specific area, and fast unidirectional charge transfer [1,2]. Pristine $TiO_{2}$ has a band gap energy of 3.0 – 3.2 eV, making the material inefficient as a photoelectrode in PECWS, since absorption is limited to the UV region of the electromagnetic spectrum. Narrowing the band gap energy consequently extends its absorption into the visible region, which improves the photocurrent density [2,3].
In this work, the envisaged surface modified $TiO_{2}$ photoelectrodes are fabricated through a multi-step electrochemical anodization process. The final anodization step detaches the crystalline $TiO_{2}$ nanotube film from the opaque titanium substrate. Thereafter, the film is transferred and pasted onto transparent fluorine-doped tin oxide (FTO) glass. Surface modifications of the nanostructured thin film are achieved through successive ionic layer adsorption reaction (SILAR) to deposit nanostructured metal oxides. The synthesized samples are characterized by X-ray diffraction, SEM, EDS, TEM and UV-Visible spectroscopy.
The results confirm the impregnation of $TiO_{2}$ by copper oxide nanoparticles. The optical characterization indicates a red shift in the absorption edge of the $CuO/TiO_{2}$ towards the visible light range. The effect of the number of SILAR cycles on the absorption edge has also been investigated in this study. The structural characterization reveals that the loading of CuO on the $CuO/TiO_{2}$ nanotubes does not alter the morphology of the nanotubes.
This work demonstrates a facile method to prepare $TiO_{2}$ nanostructured heterojunction thin films on a transparent substrate, which could be a promising photoelectrode.
Future work includes optimizing the fabrication process of the photoelectrodes, optical and electrochemical characterization and thereafter, PECWS experiments and hydrogen evolution efficiency measurements.
Key words: $TiO_{2}$ nanotube arrays, CuO nanoparticles, SILAR, heterojunction, photoelectrode.
References
- Lixia, S., Jing, Z., Yudong, Z. & Yangbo, Z., 2015. Preparation of $CuO/TiO_{2}$ nanotube arrays and their photoelectrochemical properties as hydrogen-evolving photoanode. Solar Hydrogen and Nanotechnology.
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Loı¨, A., Vasile, H., Margrit, H. & ken, L. S., 2013. $Cu_{2}O$, Fabrication of p/n heterojunctions by electrochemical deposition of onto $TiO_{2}$ nanotubes. Comptes Rendus Chimie, p. 89 -95.
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Marica, M., Roberto, A., Laura, C. & Ilaria, D. S., 2020. Hydrogen production through photoreforming processes over $CuO/TiO_{2}$ composite materials: A mini-review. International Journal of Hydrogen Energy, Issue 45, p. 28531-28552.
Level for award;(Hons, MSc, PhD, N/A)?
MSc
| Apply to be considered for a student ; award (Yes / No)? | yes |
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