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Machreki M, Chouki T, Tyuliev G, Fanetti M, Valant M, Arčon D, Pregelj M, Emin S. The Role of Lattice Defects on the Optical Properties of TiO 2 Nanotube Arrays for Synergistic Water Splitting. ACS OMEGA 2023; 8:33255-33265. [PMID: 37744782 PMCID: PMC10515401 DOI: 10.1021/acsomega.3c00965] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 08/08/2023] [Indexed: 09/26/2023]
Abstract
In this study, we report a facile one-step chemical method to synthesize reduced titanium dioxide (TiO2) nanotube arrays (NTAs) with point defects. Treatment with NaBH4 introduces oxygen vacancies (OVs) in the TiO2 lattice. Chemical analysis and optical studies indicate that the OV density can be significantly increased by changing reduction time treatment, leading to higher optical transmission of the TiO2 NTAs and retarded carrier recombination in the photoelectrochemical process. A cathodoluminescence (CL) study of reduced TiO2 (TiO2-x) NTAs revealed that OVs contribute significantly to the emission bands in the visible range. It was found that the TiO2 NTAs reduced for a longer duration exhibited a higher concentration of OVs. A typical CL spectrum of TiO2 was deconvoluted to four Gaussian components, assigned to F, F+, and Ti3+ centers. X-ray photoelectron spectroscopy measurements were used to support the change in the surface chemical bonding and electronic valence band position in TiO2. Electron paramagnetic resonance spectra confirmed the presence of OVs in the TiO2-x sample. The prepared TiO2-x NTAs show an enhanced photocurrent for water splitting due to pronounced light absorption in the visible region, enhanced electrical conductivity, and improved charge transportation.
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Affiliation(s)
- Manel Machreki
- Materials
Research Laboratory, University of Nova
Gorica, Vipavska 11c, 5270 Ajdovščina, Slovenia
| | - Takwa Chouki
- Materials
Research Laboratory, University of Nova
Gorica, Vipavska 11c, 5270 Ajdovščina, Slovenia
| | - Georgi Tyuliev
- Institute
of Catalysis, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Bldg. 11, Sofia 1113, Bulgaria
| | - Mattia Fanetti
- Materials
Research Laboratory, University of Nova
Gorica, Vipavska 11c, 5270 Ajdovščina, Slovenia
| | - Matjaž Valant
- Materials
Research Laboratory, University of Nova
Gorica, Vipavska 11c, 5270 Ajdovščina, Slovenia
| | - Denis Arčon
- Institute
“Jožef Stefan”, Jamova 39, 1000 Ljubljana, Slovenia
- Faculty
of Mathematics and Physics, University of
Ljubljana, Jadranska
c. 19, SI-1000 Ljubljana, Slovenia
| | - Matej Pregelj
- Institute
“Jožef Stefan”, Jamova 39, 1000 Ljubljana, Slovenia
| | - Saim Emin
- Materials
Research Laboratory, University of Nova
Gorica, Vipavska 11c, 5270 Ajdovščina, Slovenia
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Micro-Raman analysis of titanium oxide/carbon nanotubes-based nanocomposites for hydrogen sensing applications. J SOLID STATE CHEM 2010. [DOI: 10.1016/j.jssc.2010.08.018] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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