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Study of Oxygen Vacancies in TiO2 Nanostructures and Their Relationship with Photocatalytic Activity. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12073690] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
In this research work, we present the synthesis and characterization of four different TiO2 structures, such as nanotubes, nanocavities, nanosheets assembled on nanocavities and nanobowls assembled on nanocavities, prepared by electrochemical anodization using organic electrolytes. After synthesis, the structures were thermally annealed to pass from the amorphous phase to the anatase phase, which is one of the most important crystalline structures of TiO2 due to its high photocatalytic activity and stability. The unique morphology and topography were studied using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The elemental composition was determined by energy-dispersive X-ray spectroscopy (EDS). The anatase phase was verified by Raman microscopy and X-ray diffraction (XRD), the band gap energy was calculated by the Kubelka–Munk function, and the main defect states that generate the emission, as well as their lifetime, were determined by photoluminescence spectroscopy and time response photoluminescence (TRPL), respectively. The TiO2 nanomaterials were tested as catalysts in the photodegradation of a solution of methylene blue using a UV lamp at room temperature. The results showed complex morphologies and different surface roughness areas of these nanomaterials. Furthermore, a relationship between defect states, band gap energy, and photocatalytic activity was established. We found that the catalytic activity was improved as an effect of geometric parameters and oxygen vacancies.
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Rufai Y, Chandren S, Basar N. Influence of Solvents' Polarity on the Physicochemical Properties and Photocatalytic Activity of Titania Synthesized Using Deinbollia pinnata Leaves. Front Chem 2020; 8:597980. [PMID: 33344417 PMCID: PMC7744779 DOI: 10.3389/fchem.2020.597980] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 11/09/2020] [Indexed: 12/02/2022] Open
Abstract
Nanotechnology is one of the most interesting areas of research due to its flexibility to improve or form new products from nanoparticles (NPs), and as a fast, greener, more eco-friendly and sustainable solution to technological and environmental challenges. Among metal oxides of photocatalytic performance, the use of titania (TiO2) as photocatalyst is most popular due to its unique optical and electronic properties. Despite the wide utilization, the synthesis of TiO2 NPs bears many disadvantages: it utilizes various less environmental-friendly chemicals, high cost, requires high pressure and energy, and potentially hazardous physical and chemical methods. Hence, the development of green synthesis approach with eco-friendly natural products can be used to overcome these adverse effects. In this work, TiO2 NPs have been prepared by using Deinbollia pinnata leaves extracts, obtained by different solvents (n-hexane, ethyl acetate, and ethanol) with different polarities. The extracts acted as the reducing agent, while titanium isopropoxide as the precursor and water as the solvent. X-ray diffraction (XRD) pattern confirmed the synthesized TiO2 consist of anatase phase in high purity, with average crystallite size in the range of 19–21 nm. Characterization by using field emission scanning electron microscopy (FESEM) showed the TiO2 NPs possess a uniform semi-spherical shape in the size range of 33–48 nm. The energy dispersive X-ray (EDX) spectra of green TiO2 NPs showed two peaks for the main elements of Ti (61 Wt.%) and O (35 Wt.%). The band-gap energy of 3.2 eV was determined using UV-Vis spectroscopy. From the nitrogen sorption analysis, type V isotherm of the material was obtained, with BET surface area of 31.77 m2/g. The photocatalytic activity of synthesized TiO2 was evaluated for photodegradation of methyl orange (MO) under UV light irradiation. Based on the results, it is shown that TiO2 NPs synthesized with D. pinnata leaves extracted using ethyl acetate showed the most effective photodegradation performance, achieving 98.7% of MO conversion within 150 min. It can be concluded that the use of plant extracts in synthesis with TiO2 managed to produce highly crystalline anatase TiO2 with superior photocatalytic activity in the photodegradation of organic dye.
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Affiliation(s)
- Yakubu Rufai
- Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Johor Bahru, Malaysia.,Department of Chemistry, Federal College of Education (FCE), Okene, Nigeria
| | - Sheela Chandren
- Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Johor Bahru, Malaysia.,Centre for Sustainable Nanomaterials, Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, Johor Bahru, Malaysia
| | - Norazah Basar
- Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Johor Bahru, Malaysia
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Katal R, Masudy-Panah S, Sabbaghan M, Hossaini Z, Davood Abadi Farahani MH. Photocatalytic degradation of triclosan by oxygen defected CuO thin film. Sep Purif Technol 2020. [DOI: 10.1016/j.seppur.2020.117239] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ghobadi TGU, Ghobadi A, Soydan MC, Vishlaghi MB, Kaya S, Karadas F, Ozbay E. Strong Light-Matter Interactions in Au Plasmonic Nanoantennas Coupled with Prussian Blue Catalyst on BiVO 4 for Photoelectrochemical Water Splitting. CHEMSUSCHEM 2020; 13:2577-2588. [PMID: 32157799 DOI: 10.1002/cssc.202000294] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/06/2020] [Indexed: 05/07/2023]
Abstract
A facial and large-scale compatible fabrication route is established, affording a high-performance heterogeneous plasmonic-based photoelectrode for water oxidation that incorporates a CoFe-Prussian blue analog (PBA) structure as the water oxidation catalytic center. For this purpose, an angled deposition of gold (Au) was used to selectively coat the tips of the bismuth vanadate (BiVO4 ) nanostructures, yielding Au-capped BiVO4 (Au-BiVO4 ). The formation of multiple size/dimension Au capping islands provides strong light-matter interactions at nanoscale dimensions. These plasmonic particles not only enhance light absorption in the bulk BiVO4 (through the excitation of Fabry-Perot (FP) modes) but also contribute to photocurrent generation through the injection of sub-band-gap hot electrons. To substantiate the activity of the photoanodes, the interfacial electron dynamics are significantly improved by using a PBA water oxidation catalyst (WOC) resulting in an Au-BiVO4 /PBA assembly. At 1.23 V (vs. RHE), the photocurrent value for a bare BiVO4 photoanode was obtained as 190 μA cm-2 , whereas it was boosted to 295 μA cm-2 and 1800 μA cm-2 for Au-BiVO4 and Au-BiVO4 /PBA, respectively. Our results suggest that this simple and facial synthetic approach paves the way for plasmonic-based solar water splitting, in which a variety of common metals and semiconductors can be employed in conjunction with catalyst designs.
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Affiliation(s)
- T Gamze Ulusoy Ghobadi
- UNAM-National Nanotechnology Research Center, Institute of Materials Science and Nanotechnology, Bilkent University, 6800, Ankara, Turkey
| | - Amir Ghobadi
- Department of Electrical and Electronics Engineering, Bilkent University, 06800, Ankara, Turkey
- NANOTAM-Nanotechnology Research Center, Bilkent University, 06800, Ankara, Turkey
| | - Mahmut Can Soydan
- Department of Electrical and Electronics Engineering, Bilkent University, 06800, Ankara, Turkey
- NANOTAM-Nanotechnology Research Center, Bilkent University, 06800, Ankara, Turkey
| | - Mahsa Barzgar Vishlaghi
- Chemistry Department, Koc University, Istanbul, 34450, Turkey
- TUPRAS Energy Center (KUTEM), Koc University, Istanbul, 34450, Turkey
| | - Sarp Kaya
- Chemistry Department, Koc University, Istanbul, 34450, Turkey
- TUPRAS Energy Center (KUTEM), Koc University, Istanbul, 34450, Turkey
| | - Ferdi Karadas
- UNAM-National Nanotechnology Research Center, Institute of Materials Science and Nanotechnology, Bilkent University, 6800, Ankara, Turkey
- Department of Chemistry, Faculty of Science, Bilkent University, 06800, Ankara, Turkey
| | - Ekmel Ozbay
- UNAM-National Nanotechnology Research Center, Institute of Materials Science and Nanotechnology, Bilkent University, 6800, Ankara, Turkey
- Department of Electrical and Electronics Engineering, Bilkent University, 06800, Ankara, Turkey
- NANOTAM-Nanotechnology Research Center, Bilkent University, 06800, Ankara, Turkey
- Department of Physics, Faculty of Science, Bilkent University, 06800, Ankara, Turkey
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Visible Light Photodegradation of Formaldehyde over TiO 2 Nanotubes Synthesized via Electrochemical Anodization of Titanium Foil. NANOMATERIALS 2020; 10:nano10010128. [PMID: 31936704 PMCID: PMC7022416 DOI: 10.3390/nano10010128] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/03/2020] [Accepted: 01/05/2020] [Indexed: 11/23/2022]
Abstract
In this study, a series of TiO2 nanotubes (NTs) were synthesized employing electrochemical anodization of titanium foil in an ionic liquid solution containing a mixture of glycerol and choline chloride, acting as electrolyte. The as-synthesized TiO2 NTs were calcined at 350, 450, or 550 °C for a 2 h duration to investigate the influence of calcination temperature on NTs formation, morphology, surface properties, crystallinity, and subsequent photocatalytic activity for visible light photodegradation of gaseous formaldehyde (HCHO). Results showed that the calcination temperature has a significant effect on the structure and coverage of TiO2 NTs on the surface. Freshly synthesized TiO2 NTs showed better-ordered structure compared to calcined samples. There was significant pore rupture with increasing calcination temperature. The transformation from anatase to rutile phase appeared after calcination at 450 °C and the weight fraction of the rutile phase increased from 19% to 36% upon increasing the calcination temperature to 550 °C. The band gaps of the TiO2 NTs were in the range from 2.80 to 2.74 eV, shifting the active region of the materials to visible light. The presence of mixed anatase–rutile TiO2 phases in the sample calcined at 450 °C showed enhanced photoactivity, which was confirmed by the 21.56 mg∙L−1∙g−1 removal of gaseous formaldehyde under 120 min of visible light irradiation and displayed enhanced quantum yield, ∅HCHO of 17%.
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The Influence of the Parameters of a Gold Nanoparticle Deposition Method on Titanium Dioxide Nanotubes, Their Electrochemical Response, and Protein Adsorption. BIOSENSORS-BASEL 2019; 9:bios9040138. [PMID: 31756994 PMCID: PMC6956335 DOI: 10.3390/bios9040138] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 11/06/2019] [Accepted: 11/11/2019] [Indexed: 12/20/2022]
Abstract
The goal of this research was to find the best conditions to prepare titanium dioxide nanotubes (TNTs) modified with gold nanoparticles (AuNPs). This paper, for the first time, reports on the influence of the parameters of cyclic voltammetry process (CV) -based AuNP deposition, i.e., the number of cycles and the concentration of gold salt solution, on corrosion resistance and the capacitance of TNTs. Another innovation was to fabricate AuNPs with well-formed spherical geometry and uniform distribution on TNTs. The AuNPs/TNTs were characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, and open-circuit potential measurement. From the obtained results, the correlation between the deposition process parameters, the AuNP diameters, and the electrical conductivity of the TNTs was found in a range from 14.3 ± 1.8 to 182.3 ± 51.7 nm. The size and amount of the AuNPs could be controlled by the number of deposition cycles and the concentration of the gold salt solution. The modification of TNTs using AuNPs facilitated electron transfer, increased the corrosion resistance, and caused better adsorption properties for bovine serum albumin.
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Silva-Moraes MO, Garcia-Basabe Y, de Souza RFB, Mota AJ, Passos RR, Galante D, Fonseca Filho HD, Romaguera-Barcelay Y, Rocco MLM, Brito WR. Geometry-dependent DNA-TiO 2 immobilization mechanism: A spectroscopic approach. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 199:349-355. [PMID: 29635179 DOI: 10.1016/j.saa.2018.03.081] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 03/28/2018] [Accepted: 03/30/2018] [Indexed: 06/08/2023]
Abstract
DNA nucleotides are used as a molecular recognition system on electrodes modified to be applied in the detection of various diseases, but immobilization mechanisms, as well as, charge transfers are not satisfactorily described in the literature. An electrochemical and spectroscopic study was carried out to characterize the molecular groups involved in the direct immobilization of DNA structures on the surface of nanostructured TiO2 with the aim of evaluating the influence of the geometrical aspects. X-ray photoelectron spectroscopy at O1s and P2p core levels indicate that immobilization of DNA samples occurs through covalent (POTi) bonds. X-ray absorption spectra at the Ti2p edge reinforce this conclusion. A new species at 138.5eV was reported from P2p XPS spectra analysis which plays an important role in DNA-TiO2 immobilization. The POTi/OTi ratio showed that quantitatively the DNA immobilization mechanism is dependent on their geometry, becoming more efficient for plasmid ds-DNA structures than for PCR ds-DNA structures. The analysis of photoabsorption spectra at C1s edge revealed that the molecular groups that participate in the C1s→LUMO electronic transitions have different pathways in the charge transfer processes at the DNA-TiO2 interface. Our results may contribute to additional studies of immobilization mechanisms understanding the influence of the geometry of different DNA molecules on nanostructured semiconductor and possible impact to the charge transfer processes with application in biosensors or aptamers.
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Affiliation(s)
- M O Silva-Moraes
- Department of Chemistry, Federal University of Amazonas, Manaus, Amazonas 69067-005, Brazil
| | - Y Garcia-Basabe
- Institute of Science of Life and Nature - ILACVN, Federal University of Latin-American Integration, Foz do Iguaçu 85866-000, PR, Brazil
| | - R F B de Souza
- Department of Chemistry, Federal University of Amazonas, Manaus, Amazonas 69067-005, Brazil
| | - A J Mota
- Faculty of Agricultural Sciences, Federal University of Amazonas, Manaus, Amazonas 69067-005, Brazil
| | - R R Passos
- Department of Chemistry, Federal University of Amazonas, Manaus, Amazonas 69067-005, Brazil
| | - D Galante
- Brazilian Synchrotron Light Laboratory LNLS/CNPEM, Campinas, São Paulo 13083-970, Brazil
| | - H D Fonseca Filho
- Department of Physics, Federal University of Amazonas, Manaus, Amazonas 69067-005, Brazil
| | - Y Romaguera-Barcelay
- Department of Physics, Federal University of Amazonas, Manaus, Amazonas 69067-005, Brazil
| | - M L M Rocco
- Institute of Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro 21941-901, Brazil
| | - W R Brito
- Department of Chemistry, Federal University of Amazonas, Manaus, Amazonas 69067-005, Brazil.
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Gaidi M, Trabelsi K, Hajjaji A, Chourou ML, Alhazaa AN, Bessais B, El Khakani MA. Optimizing the photochemical conversion of UV-vis light of silver-nanoparticles decorated TiO 2 nanotubes based photoanodes. NANOTECHNOLOGY 2018; 29:015703. [PMID: 29082898 DOI: 10.1088/1361-6528/aa96c3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Homogeneous decoration of TiO2 nanotubes (NTs) by Ag metallic nanoparticles (NPs) was carried out by a relatively simple photoreduction process. This Ag-NPs decoration was found to improve the photoconversion efficiency of the TiO2-NTs based photoanodes. The x-ray photoelectron spectroscopy and x-ray diffraction analyses confirmed that all the Ag-NPs are metallic and the underlying TiO2-NTs crystallize in the anatase phase after their annealing at 400 °C, respectively. Transmission electron microscopy observations have confirmed the effective decoration of the TiO2-NTs' surface by Ag-NPs, and allowed to measure the average Ag-NPs size, which was found to increase linearly from (4 ± 2) nm to (16 ± 4) nm when the photoreduction time is increased from 5 to 20 min. The diffuse reflectivity of the Ag-NPs decorated TiO2-NTs was found to decrease significantly as compared to the undecorated TiO2-NTs. Interestingly, the Ag-NPs decorated TiO2-NTs exhibited a significantly enhanced photochemical response, under visible radiation, with regards to the undecorated NTs. This enhancement was found to reach its maximum for the TiO2-NTs decorated with Ag-NPs having the optimal average diameter of ∼8.5 nm. The maximum photoconversion efficiency of Ag-NPs decorated TiO2-NTs was about two times greater than for the undecorated ones. This improved photo-electro-chemical response is believed to be associated with the additional absorption of visible light of Ag-NPs through the localized surface plasmon resonance phenomenon. This interpretation is supported by the fact that the photoluminescence intensity of the Ag-NPs decorated TiO2-NTs was found to decrease significantly as compared to undecorated NTs, due to charge carriers trapping in the Ag NPs. This demonstrates that Ag-NPs decoration promotes photogenerated charges separation in the TiO2-NTs, increasing thereby their capacity for current photogeneration. The surface decoration of TiO2 NTs by noble metals NPs is expected to impact positively the use of TiO2-NTs based photoanodes in some energetic applications such as hydrogen generation and photo-electrochemical solar cells.
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Affiliation(s)
- M Gaidi
- Center of Advanced Materials Research, University of Sharjah, PO Box 27272, Sharjah, United Arab Emirates. Laboratoire de Photovoltaïque, Centre de Recherches et des Technologies de l'Energie, Technopole de Borj-Cédria, BP 95, 2050 Hammam-Lif, Tunisia
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Xie Z, Shuang S, Ma L, Zhu F, Liu X, Zhang Z. Annealing effect on the photoelectrochemical and photocatalytic performance of TiO2 nanorod arrays. RSC Adv 2017. [DOI: 10.1039/c7ra09801d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The photoelectrochemical and photocatalytic properties of TiO2 nanorod arrays annealed in the air were investigated.
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Affiliation(s)
- Zheng Xie
- State Key Laboratory for New Ceramics and Fine Processing
- School of Materials Science and Engineering
- Tsinghua University
- Beijing 100084
- China
| | - Shuang Shuang
- State Key Laboratory for New Ceramics and Fine Processing
- School of Materials Science and Engineering
- Tsinghua University
- Beijing 100084
- China
| | - Lingwei Ma
- State Key Laboratory for New Ceramics and Fine Processing
- School of Materials Science and Engineering
- Tsinghua University
- Beijing 100084
- China
| | - Fei Zhu
- State Key Laboratory for New Ceramics and Fine Processing
- School of Materials Science and Engineering
- Tsinghua University
- Beijing 100084
- China
| | | | - Zhengjun Zhang
- State Key Laboratory for New Ceramics and Fine Processing
- School of Materials Science and Engineering
- Tsinghua University
- Beijing 100084
- China
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Kim SE, Woo JY, Kang SY, Min BK, Lee JK, Lee SW. A facile general route for ternary Fe 2 O 3 @TiO 2 @nanometal (Au, Ag) composite as a high-performance and recyclable photocatalyst. J IND ENG CHEM 2016. [DOI: 10.1016/j.jiec.2016.07.060] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Sano N, Matsuoka S, Tamon H. Purification of titanate nanotubes using a mesh-stacked dielectrophoretic separator equipped with carbon nanotube electrodes. Chem Eng Sci 2014. [DOI: 10.1016/j.ces.2014.01.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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