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Misra SK, Andronenko SI, Tipikin D, Freed JH, Somani V, Prakash O. Study of paramagnetic defect centers in as-grown and annealed TiO 2 anatase and rutile nanoparticles by a variable-temperature X-band and high-frequency (236 GHz) EPR. JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS 2016; 401:495-505. [PMID: 27041794 PMCID: PMC4815036 DOI: 10.1016/j.jmmm.2015.10.072] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Detailed EPR investigations on as-grown and annealed TiO2 nanoparticles in the anatase and rutile phases were carried out at X-band (9.6 GHz) at 77, 120-300 K and at 236 GHz at 292 K. The analysis of EPR data for as-grown and annealed anatase and rutile samples revealed the presence of several paramagnetic centers: Ti3+, O-, adsorbed oxygen (O2-) and oxygen vacancies. On the other hand, in as-grown rutile samples, there were observed EPR lines due to adsorbed oxygen (O2-) and the Fe3+ ions in both Ti4+ substitutional positions, with and without coupling to an oxygen vacancy in the near neighborhood. Anatase nanoparticles were completely converted to rutile phase when annealed at 1000° C, exhibiting EPR spectra similar to those exhibited by the as-grown rutile nanoparticles. The high-frequency (236 GHz) EPR data on anatase and rutile samples, recorded in the region about g = 2.0 exhibit resolved EPR lines, due to O- and O2- ions enabling determination of their g-values with higher precision, as well as observation of hyperfine sextets due to Mn2+ and Mn4+ ions in anatase.
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Affiliation(s)
- S K Misra
- Physics Department, Concordia University, 1455 de Maisonneuve Blvd West, Montreal, QC H3G 1M8, Canada
| | - S I Andronenko
- Physics Department, Concordia University, 1455 de Maisonneuve Blvd West, Montreal, QC H3G 1M8, Canada
| | - D Tipikin
- ACERT Biomedical Center, Baker Laboratory, Cornell University, Ithaca, NY 14853-1301, USA
| | - J H Freed
- ACERT Biomedical Center, Baker Laboratory, Cornell University, Ithaca, NY 14853-1301, USA
| | - V Somani
- Department of Metallurgical Engineering and Material Science, Indian Institute of Technology, Bombay, Powai, Mumbai 400076, India
| | - Om Prakash
- Department of Metallurgical Engineering and Material Science, Indian Institute of Technology, Bombay, Powai, Mumbai 400076, India
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Abstract
Stainless steel anode covered with layer film of TiO2doped with manganese was utilized to decompose 4-nitroaniline in rectangular borosilicate glass reactor, while stainless steel mesh was chosen as cathode; the anode and cathode were connected to the direct-current power; meantime two 60 W (λmax= 365 nm) UV lamps were used as light source. The microstructures on TiO2before and after being doped with manganese were analyzed by energy disperse X-ray (EDX) and X-ray diffraction (XRD). The performance of degradation of 4-nitroaniline was evaluated by analyzing cracking ratio of 4-nitroaniline ring, the chemical oxygen demand (COD), and total organic carbon (TOC) in remaining solution. Monitored parameters during all the photocatalytic reaction including dissolved oxygen, direct voltage, and radiation dosage of ultraviolet rays were investigated. When dissolved oxygen concentration, direct voltage, and radiation dosage of ultraviolet rays were, respectively, equivalent to 9 mg/L, 24 V, and 1200 μW/cm2, the degradation ratio of 4-nitroaniline reached maximum. The experimental results indicated that cracking ratio of 4-nitroaniline ring and the removal ratio of COD and TOC were, respectively, more than 99%, 85%, and 80% when reaction was run for 10 hours. The values of COD and TOC were, respectively, less than 16 mg/L and 8 mg/L while the experiment was finished.
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Ma Y, Wang X, Jia Y, Chen X, Han H, Li C. Titanium Dioxide-Based Nanomaterials for Photocatalytic Fuel Generations. Chem Rev 2014; 114:9987-10043. [DOI: 10.1021/cr500008u] [Citation(s) in RCA: 1845] [Impact Index Per Article: 184.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Yi Ma
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Dalian National Laboratory for Clean Energy, 457
Zhongshan Road, Dalian 116023, China
| | - Xiuli Wang
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Dalian National Laboratory for Clean Energy, 457
Zhongshan Road, Dalian 116023, China
| | - Yushuai Jia
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Dalian National Laboratory for Clean Energy, 457
Zhongshan Road, Dalian 116023, China
| | - Xiaobo Chen
- Department
of Chemistry, College of Arts and Sciences, University of Missouri-Kansas City, 5100 Rockhill Road, Kansas City, Missouri 64110, United States
| | - Hongxian Han
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Dalian National Laboratory for Clean Energy, 457
Zhongshan Road, Dalian 116023, China
| | - Can Li
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Dalian National Laboratory for Clean Energy, 457
Zhongshan Road, Dalian 116023, China
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Rajashekhar KE, Devi LG. Polymorphic phase transformation of Degussa P25 TiO2 by the chelation of diaminopyridine on TiO62− octahedron: Correlation of anatase to rutile phase ratio on the photocatalytic activity. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.molcata.2013.02.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Zhang J, Wages M, Cox SB, Maul JD, Li Y, Barnes M, Hope-Weeks L, Cobb GP. Effect of titanium dioxide nanomaterials and ultraviolet light coexposure on African clawed frogs (Xenopus laevis). ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2012; 31:176-183. [PMID: 22012895 DOI: 10.1002/etc.718] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 01/18/2011] [Accepted: 03/14/2011] [Indexed: 05/31/2023]
Abstract
Titanium dioxide nanomaterials (nano-TiO(2) ) exhibit stronger photochemical oxidation/reduction capacity compared with their bulk counterparts, but the effectiveness of nano-TiO(2) interaction with ultraviolet (UV) light strongly depends on particle size. In this study, the dependence of nano-TiO(2) toxicity on particle size and interaction with UV light were investigated. Toxicity tests with Xenopus laevis included eight concentrations of nano-TiO(2) in the presence of either white light or UVA (315-400 nm). We quantified viability and growth of Xenopus laevis. Results showed that, regardless of UV light exposure, increasing TiO(2) concentration decreased X. laevis survival (p < 0.05). Coexposure to 5-nm TiO(2) and UVA caused near-significant decreases in X. laevis survival (p = 0.08). Coexposure to 10-nm TiO(2) and UVA significantly decreased X. laevis survival (p = 0.005). However, coexposure to 32-nm TiO(2) and UVA had no statistical effect on X. laevis survival (p = 0.8). For all three particle sizes, whether alone or with UV light, the nano-TiO(2) concentrations significantly affected growth of tadpoles as determined by total body length, snout-vent length, and developmental stage. High-concentration TiO(2) solutions suppressed tadpole body length and delayed developmental stages. Further research to explore reasons for the growth and mortality in tadpoles is still underway in our laboratory. Given the widespread application of nano-TiO(2) , our results may be useful in the management of nano-TiO(2) released from industrial, municipal, and nonpoint sources.
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Affiliation(s)
- Junling Zhang
- Department of Environmental Toxicology, Texas Tech University, Lubbock, Texas, USA
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Kumar SG, Devi LG. Review on Modified TiO2 Photocatalysis under UV/Visible Light: Selected Results and Related Mechanisms on Interfacial Charge Carrier Transfer Dynamics. J Phys Chem A 2011; 115:13211-41. [DOI: 10.1021/jp204364a] [Citation(s) in RCA: 1519] [Impact Index Per Article: 116.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- S. Girish Kumar
- Department of Post Graduate Studies in Chemistry, Bangalore University, Central College City Campus, Dr. Ambedkar Street, Bangalore-560001, Karnataka, India
| | - L. Gomathi Devi
- Department of Post Graduate Studies in Chemistry, Bangalore University, Central College City Campus, Dr. Ambedkar Street, Bangalore-560001, Karnataka, India
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Facile synthesis and photocatalytic property of bicrystalline TiO2/rectorite composites. Colloids Surf A Physicochem Eng Asp 2011. [DOI: 10.1016/j.colsurfa.2011.03.043] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Lakshmipathi Naik GD, Kottam N, Shivashankar GK. Photo Catalytic Degradation of Azo Dyes over Mn2+ Doped TiO2 Catalyst under UV/Solar Light: An Insight to the Route of Electron Transfer in the Mixed Phase of Anatase and Rutile. CHINESE J CHEM 2010. [DOI: 10.1002/cjoc.201090356] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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9
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Enhanced photocatalytic activity of transition metal ions Mn2+, Ni2+ and Zn2+ doped polycrystalline titania for the degradation of Aniline Blue under UV/solar light. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.molcata.2010.05.021] [Citation(s) in RCA: 179] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Li C, Wang WD. Photocatalytic Degradation of Phenol over MWCNTs-TiO2Composite Catalysts with Different Diameters. CHINESE J CHEM PHYS 2009. [DOI: 10.1088/1674-0068/22/04/423-428] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Gomathi Devi L, Kottam N, Girish Kumar S, Anantha Raju KS. Mechanism of Charge Transfer in the Transition Metal Ion Doped TiO2 with Bicrystalline Framework of Anatase and Rutile: Photocatalytic and Photoelectrocatalytic Activity. Catal Letters 2009. [DOI: 10.1007/s10562-009-0015-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Influence of Mn2+ and Mo6+ dopants on the phase transformations of TiO2 lattice and its photo catalytic activity under solar illumination. CATAL COMMUN 2009. [DOI: 10.1016/j.catcom.2008.11.041] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Sumfleth J, de Almeida Prado LA, Sriyai M, Schulte K. Titania-doped multi-walled carbon nanotubes epoxy composites: Enhanced dispersion and synergistic effects in multiphase nanocomposites. POLYMER 2008. [DOI: 10.1016/j.polymer.2008.09.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Chang H, Kim SJ, Jang HD, Choi JW. Synthetic routes for titania nanoparticles in the flame spray pyrolysis. Colloids Surf A Physicochem Eng Asp 2008. [DOI: 10.1016/j.colsurfa.2007.04.111] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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The solid–solid interface: Explaining the high and unique photocatalytic reactivity of TiO2-based nanocomposite materials. Chem Phys 2007. [DOI: 10.1016/j.chemphys.2007.05.023] [Citation(s) in RCA: 251] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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