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Andrade ÓR, Camarillo R, Martínez F, Jiménez C, Rincón J. Impact of the Precursor on the Physicochemical Properties and Photoactivity of TiO 2 Nanoparticles Produced in Supercritical CO 2. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2328. [PMID: 37630913 PMCID: PMC10459058 DOI: 10.3390/nano13162328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/09/2023] [Accepted: 08/11/2023] [Indexed: 08/27/2023]
Abstract
The synthesis of TiO2 nanoparticles (NPs) in supercritical media has been reported over the last two decades. However, very few studies have compared the physicochemical characteristics and photoactivity of the TiO2 powders produced from different precursors, and even fewer have investigated the effect of using different ratios of hydrolytic agent/precursor (HA/P) on the properties of the semiconductor. To bridge this knowledge gap, this research focuses on the synthesis and characterization of TiO2 NPs obtained in a supercritical CO2 medium from four different TiO2 precursors, namely diisopropoxytitanium bis (acetylacetonate) (TDB), titanium (IV) isopropoxide (TIP), titanium (IV) butoxide (TBO), and titanium (IV) 2-ethylhexyloxide (TEO). Further, the effect of various HA/P ratios (10, 20, 30, and 40 mol/mol) when using ethanol as a hydrolytic agent has also been analyzed. Results obtained have shown that the physicochemical properties of the catalysts are not significantly affected by these variables, although some differences do exist between the synthesized materials and their catalytic performances. Specifically, photocatalysts obtained from TIP and TEO at the higher HA/P ratios (HA/P = 30 and HA/P = 40) led to higher CO2 photoconversions (6.3-7 µmol·g-1·h-1, Apparent Quantum Efficiency < 0.1%), about three times higher than those attained with commercial TiO2 P-25. These results have been imputed to the fact that these catalysts exhibit appropriate values of crystal size, surface area, light absorption, and charge transfer properties.
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Affiliation(s)
| | - Rafael Camarillo
- Department of Chemical Engineering, Faculty of Environmental Sciences and Biochemistry, University of Castilla-La Mancha, 45071 Toledo, Spain
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Rosales Medina PY, Avelar Muñoz F, Flores Sigala E, Rosales RG, Berumen Torres JA, Araiza Ibarra JDJ, Tototzintle Huitle H, Méndez García VH, Ortega Sigala JJ. Growth of Nanocolumnar TiO 2 Bilayer by Direct Current Reactive Magnetron Sputtering in Glancing-Angle Deposition Configuration for High-Quality Electron Transport Layer. MICROMACHINES 2023; 14:1483. [PMID: 37630019 PMCID: PMC10456511 DOI: 10.3390/mi14081483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/18/2023] [Accepted: 07/20/2023] [Indexed: 08/27/2023]
Abstract
The electron transport layer (ETL) plays a crucial role in solar cell technology, particularly in perovskite solar cells (PSCs), where nanostructured TiO2 films have been investigated as superior ETLs compared to compact TiO2. In this study, we explored the nanocolumnar growth of TiO2 in the anatase phase for bilayer thin films by DC reactive magnetron sputtering (MS) technique and glancing-angle deposition (GLAD). For the growth of the compact TiO2 layer, it was found that the crystalline quality of the films is strongly dependent on the sputtering power, and the samples deposited at 120 and 140 W are those with the best crystalline quality. However, for the nanocolumnar layer, the reactive atmosphere composition determined the best crystalline properties. By optimizing the growth parameters, the formation of TiO2 nanocolumns with a cross-sectional diameter ranging from 50 to 75 nm was achieved. The average thickness of the films exceeded 12.71 ± 0.5 µm. All nanostructured films were grown at a constant GLAD angle of 70°, and after deposition, the measured inclination angle of the nanocolumns is very close to this, having values between 68 and 80°. Furthermore, a correlation was observed between the quality of the initial layer and the enhanced growth of the TiO2 nanocolumns. All bilayer films are highly transparent, allowing light to pass through up to 90%, and present a band gap with values between 3.7 and 3.8 eV. This article offers the experimental parameters for the fabrication of a nanocolumnar TiO2 using the magnetron sputtering technique and the glancing-angle deposition configuration.
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Affiliation(s)
- Perla Yanet Rosales Medina
- Unidad Académica de Física, Universidad Autónoma de Zacatecas, Campus Universitario II, Av. Preparatoria S/N, Col. Hidráulica, Zacatecas 98068, Mexico; (F.A.M.); (E.F.S.); (R.G.R.); (J.A.B.T.); (J.d.J.A.I.); (H.T.H.); (J.J.O.S.)
| | - Fernando Avelar Muñoz
- Unidad Académica de Física, Universidad Autónoma de Zacatecas, Campus Universitario II, Av. Preparatoria S/N, Col. Hidráulica, Zacatecas 98068, Mexico; (F.A.M.); (E.F.S.); (R.G.R.); (J.A.B.T.); (J.d.J.A.I.); (H.T.H.); (J.J.O.S.)
| | - Elida Flores Sigala
- Unidad Académica de Física, Universidad Autónoma de Zacatecas, Campus Universitario II, Av. Preparatoria S/N, Col. Hidráulica, Zacatecas 98068, Mexico; (F.A.M.); (E.F.S.); (R.G.R.); (J.A.B.T.); (J.d.J.A.I.); (H.T.H.); (J.J.O.S.)
| | - Roberto Gómez Rosales
- Unidad Académica de Física, Universidad Autónoma de Zacatecas, Campus Universitario II, Av. Preparatoria S/N, Col. Hidráulica, Zacatecas 98068, Mexico; (F.A.M.); (E.F.S.); (R.G.R.); (J.A.B.T.); (J.d.J.A.I.); (H.T.H.); (J.J.O.S.)
| | - Javier Alejandro Berumen Torres
- Unidad Académica de Física, Universidad Autónoma de Zacatecas, Campus Universitario II, Av. Preparatoria S/N, Col. Hidráulica, Zacatecas 98068, Mexico; (F.A.M.); (E.F.S.); (R.G.R.); (J.A.B.T.); (J.d.J.A.I.); (H.T.H.); (J.J.O.S.)
| | - José de Jesús Araiza Ibarra
- Unidad Académica de Física, Universidad Autónoma de Zacatecas, Campus Universitario II, Av. Preparatoria S/N, Col. Hidráulica, Zacatecas 98068, Mexico; (F.A.M.); (E.F.S.); (R.G.R.); (J.A.B.T.); (J.d.J.A.I.); (H.T.H.); (J.J.O.S.)
| | - Hugo Tototzintle Huitle
- Unidad Académica de Física, Universidad Autónoma de Zacatecas, Campus Universitario II, Av. Preparatoria S/N, Col. Hidráulica, Zacatecas 98068, Mexico; (F.A.M.); (E.F.S.); (R.G.R.); (J.A.B.T.); (J.d.J.A.I.); (H.T.H.); (J.J.O.S.)
| | - Víctor Hugo Méndez García
- CIACYT, Universidad Autónoma de San Luis Potosí, Av. Sierra Leona #550-2A, Col. Lomas de San Luis, San Luis Potosí 78210, Mexico;
| | - José Juan Ortega Sigala
- Unidad Académica de Física, Universidad Autónoma de Zacatecas, Campus Universitario II, Av. Preparatoria S/N, Col. Hidráulica, Zacatecas 98068, Mexico; (F.A.M.); (E.F.S.); (R.G.R.); (J.A.B.T.); (J.d.J.A.I.); (H.T.H.); (J.J.O.S.)
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Lizeth Katherine TN, Vendula B, Jaroslav K, Jaroslav C. Structure and Photocatalytic Properties of Ni-, Co-, Cu-, and Fe-Doped TiO 2 Aerogels. Gels 2023; 9:gels9050357. [PMID: 37232949 DOI: 10.3390/gels9050357] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 05/27/2023] Open
Abstract
TiO2 aerogels doped with Ni, Co, Cu, and Fe were prepared, and their structure and photocatalytic activity during the decomposition of a model pollutant, acid orange (AO7), were studied. After calcination at 500 °C and 900 °C, the structure and composition of the doped aerogels were evaluated and analyzed. XRD analysis revealed the presence of anatase/brookite and rutile phases in the aerogels along with other oxide phases from the dopants. SEM and TEM microscopy showed the nanostructure of the aerogels, and BET analysis showed their mesoporosity and high specific surface area of 130 to 160 m2·g-1. SEM-EDS, STEM-EDS, XPS, EPR methods and FTIR analysis evaluated the presence of dopants and their chemical state. The concentration of doped metals in aerogels varied from 1 to 5 wt.%. The photocatalytic activity was evaluated using UV spectrophotometry and photodegradation of the AO7 pollutant. Ni-TiO2 and Cu-TiO2 aerogels calcined at 500 °C showed higher photoactivity coefficients (kaap) than aerogels calcined at 900 °C, which were ten times less active due to the transformation of anatase and brookite to the rutile phase and the loss of textural properties of the aerogels.
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Affiliation(s)
- Tinoco Navarro Lizeth Katherine
- CEITEC-Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 612 00 Brno, Czech Republic
| | - Bednarikova Vendula
- CEITEC-Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 612 00 Brno, Czech Republic
| | - Kastyl Jaroslav
- CEITEC-Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 612 00 Brno, Czech Republic
| | - Cihlar Jaroslav
- CEITEC-Central European Institute of Technology, Brno University of Technology, Purkynova 656/123, 612 00 Brno, Czech Republic
- Institute of Materials Science and Engineering, Brno University of Technology, Technicka 2, 616 69 Brno, Czech Republic
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