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Photocatalytic destruction of stearic acid by TiO2 films: Evidence of highly efficient transport of photogenerated electrons and holes. J Photochem Photobiol A Chem 2023. [DOI: 10.1016/j.jphotochem.2022.114273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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2
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Alofi S, O'Rourke C, Mills A. Kinetics of stearic acid destruction on TiO 2 'self-cleaning' films revisited. Photochem Photobiol Sci 2022; 21:2061-2069. [PMID: 35945476 DOI: 10.1007/s43630-022-00278-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 07/22/2022] [Indexed: 12/15/2022]
Abstract
The photocatalytic oxidation of stearic acid, SA, by O2 is a common test method used to assess the activity of new materials and underpins a standard test for self-cleaning activity. The kinetics of this process have been well-studied and are often interpreted using one of two simple models, which are revisited here in this overview. The first model is based on the common scenario of a SA layer on top of an all-photocatalyst layer which yields zero order kinetics, for which it is suggested that all the reaction sites are occupied by SA during the bulk of the photocatalytic process. An important, but rarely noted feature of this system is that the rate of SA removal depends directly upon the fraction of absorbed ultra-bandgap radiation, which suggests that the photocatalyst particles are extensively networked, thereby allowing the photogenerated electrons and holes to move rapidly and efficiently to the surface to effect the destruction of SA. The second kinetic model has been used to describe the first order kinetics of SA removal observed for mesoporous photocatalytic films comprised of isolated photocatalyst particles, in which the SA is inside (rather than on top) of the photocatalytic film, and is developed further here. It is shown that, contrary to previous reports, this model is not appropriate for porous photocatalytic films in which the particles are extensively networked, such as ones based on powders or sol-gel films, even though they too may exhibit decay kinetics where the order is > 0. The reason for the latter kinetics appears to be a distribution of reactivities through such films, i.e. high and low activity sites.
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Affiliation(s)
- Saleh Alofi
- School of Chemistry and Chemical Engineering, Queens University Belfast, Stranmillis Road, Belfast, BT9 5AG, UK
| | - Christopher O'Rourke
- School of Chemistry and Chemical Engineering, Queens University Belfast, Stranmillis Road, Belfast, BT9 5AG, UK
| | - Andrew Mills
- School of Chemistry and Chemical Engineering, Queens University Belfast, Stranmillis Road, Belfast, BT9 5AG, UK.
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3
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Bullen JC, Heiba HF, Kafizas A, Weiss DJ. Parasitic Light Absorption, Rate Laws and Heterojunctions in the Photocatalytic Oxidation of Arsenic(III) Using Composite TiO 2 /Fe 2 O 3. Chemistry 2022; 28:e202104181. [PMID: 35114042 PMCID: PMC9306794 DOI: 10.1002/chem.202104181] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Indexed: 11/08/2022]
Abstract
Composite photocatalyst‐adsorbents such as TiO2/Fe2O3 are promising materials for the one‐step treatment of arsenite contaminated water. However, no previous study has investigated how coupling TiO2 with Fe2O3 influences the photocatalytic oxidation of arsenic(III). Herein, we develop new hybrid experiment/modelling approaches to study light absorption, charge carrier behaviour and changes in the rate law of the TiO2/Fe2O3 system, using UV‐Vis spectroscopy, transient absorption spectroscopy (TAS), and kinetic analysis. Whilst coupling TiO2 with Fe2O3 improves total arsenic removal by adsorption, oxidation rates significantly decrease (up to a factor of 60), primarily due to the parasitic absorption of light by Fe2O3 (88 % of photons at 368 nm) and secondly due to changes in the rate law from disguised zero‐order kinetics to first‐order kinetics. Charge transfer across this TiO2‐Fe2O3 heterojunction is not observed. Our study demonstrates the first application of a multi‐adsorbate surface complexation model (SCM) towards describing As(III) oxidation kinetics which, unlike Langmuir‐Hinshelwood kinetics, includes the competitive adsorption of As(V). We further highlight the importance of parasitic light absorption and catalyst fouling when designing heterogeneous photocatalysts for As(III) remediation.
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Affiliation(s)
- Jay C Bullen
- Department of Earth Science and Engineering, Faculty of Engineering Imperial College London, London, SW7 2BX, UK.,Department of Chemistry, White City Campus Imperial College London, London, W12 OBZ, UK.,London Centre for Nanotechnology, London, SW7 2AZ, UK
| | - Hany F Heiba
- Department of Earth Science and Engineering, Faculty of Engineering Imperial College London, London, SW7 2BX, UK.,Department of Chemistry, White City Campus Imperial College London, London, W12 OBZ, UK.,London Centre for Nanotechnology, London, SW7 2AZ, UK.,Marine Chemistry Department, Environmental Division National Institute of Oceanography and Fisheries, NIOF), Egypt
| | - Andreas Kafizas
- Department of Chemistry, White City Campus Imperial College London, London, W12 OBZ, UK.,The Grantham Institute, Faculty of Natural Sciences Imperial College London, London, SW7 2AZ, UK
| | - Dominik J Weiss
- Department of Earth Science and Engineering, Faculty of Engineering Imperial College London, London, SW7 2BX, UK.,Civil and Environmental Engineering, E-Quad, Princeton University, Princeton, USA
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Lee SH, Nishi H, Tatsuma T. Plasmonic behaviour and plasmon-induced charge separation of nanostructured MoO 3-x under near infrared irradiation. NANOSCALE 2018; 10:2841-2847. [PMID: 29362747 DOI: 10.1039/c7nr09477a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Plasmon-induced charge separation (PICS) allows direct conversion of localized surface plasmon resonance (LSPR) to electron flows and photoelectrochemical reactions. However, PICS has only been achieved using plasmonic noble metal nanoparticles, not with compound nanoparticles. In order to achieve compound PICS, MoO3-x nanostructures were prepared that exhibit LSPR in the near infrared region by using metal oxides or metal nanoparticles as templates. Solid-state cells based on the MoO3-x nanostructure were developed. Their photoresponse to 700-1400 nm infrared light was investigated and analyzed on the basis of their PICS mechanisms.
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Affiliation(s)
- Seung Hyuk Lee
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
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Kafizas A, Ma Y, Pastor E, Pendlebury SR, Mesa C, Francàs L, Le Formal F, Noor N, Ling M, Sotelo-Vazquez C, Carmalt CJ, Parkin IP, Durrant JR. Water Oxidation Kinetics of Accumulated Holes on the Surface of a TiO2 Photoanode: A Rate Law Analysis. ACS Catal 2017. [DOI: 10.1021/acscatal.7b01150] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Andreas Kafizas
- Department
of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K
| | - Yimeng Ma
- Department
of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K
| | - Ernest Pastor
- Department
of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K
| | - Stephanie R. Pendlebury
- Department
of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K
| | - Camilo Mesa
- Department
of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K
| | - Laia Francàs
- Department
of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K
| | - Florian Le Formal
- Laboratory
for Molecular Engineering of Optoelectronic Nanomaterials, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Nuruzzaman Noor
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Min Ling
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Carlos Sotelo-Vazquez
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Claire J. Carmalt
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - Ivan P. Parkin
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
| | - James R. Durrant
- Department
of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K
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Simpson BH, Rodríguez-López J. Redox Titrations via Surface Interrogation Scanning Electrochemical Microscopy at an Extended Semiconducting Surface for the Quantification of Photogenerated Adsorbed Intermediates. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.04.128] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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7
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Moxey M, Johnson A, El-Zubir O, Cartron M, Dinachali SS, Hunter CN, Saifullah MSM, Chong KSL, Leggett GJ. Fabrication of Self-Cleaning, Reusable Titania Templates for Nanometer and Micrometer Scale Protein Patterning. ACS NANO 2015; 9:6262-70. [PMID: 26042335 DOI: 10.1021/acsnano.5b01636] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The photocatalytic self-cleaning characteristics of titania facilitate the fabrication of reuseable templates for protein nanopatterning. Titania nanostructures were fabricated over square centimeter areas by interferometric lithography (IL) and nanoimprint lithography (NIL). With the use of a Lloyd's mirror two-beam interferometer, self-assembled monolayers of alkylphosphonates adsorbed on the native oxide of a Ti film were patterned by photocatalytic nanolithography. In regions exposed to a maximum in the interferogram, the monolayer was removed by photocatalytic oxidation. In regions exposed to an intensity minimum, the monolayer remained intact. After exposure, the sample was etched in piranha solution to yield Ti nanostructures with widths as small as 30 nm. NIL was performed by using a silicon stamp to imprint a spin-cast film of titanium dioxide resin; after calcination and reactive ion etching, TiO2 nanopillars were formed. For both fabrication techniques, subsequent adsorption of an oligo(ethylene glycol) functionalized trichlorosilane yielded an entirely passive, protein-resistant surface. Near-UV exposure caused removal of this protein-resistant film from the titania regions by photocatalytic degradation, leaving the passivating silane film intact on the silicon dioxide regions. Proteins labeled with fluorescent dyes were adsorbed to the titanium dioxide regions, yielding nanopatterns with bright fluorescence. Subsequent near-UV irradiation of the samples removed the protein from the titanium dioxide nanostructures by photocatalytic degradation facilitating the adsorption of a different protein. The process was repeated multiple times. These simple methods appear to yield durable, reuseable samples that may be of value to laboratories that require nanostructured biological interfaces but do not have access to the infrastructure required for nanofabrication.
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Affiliation(s)
- Mark Moxey
- †Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom
- ‡Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Republic of Singapore
| | - Alexander Johnson
- †Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Osama El-Zubir
- †Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Michael Cartron
- §Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Saman Safari Dinachali
- ‡Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Republic of Singapore
| | - C Neil Hunter
- §Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Mohammad S M Saifullah
- ‡Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Republic of Singapore
| | - Karen S L Chong
- ‡Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Republic of Singapore
| | - Graham J Leggett
- †Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom
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8
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Ul-Haq E, Patole S, Moxey M, Amstad E, Vasilev C, Hunter CN, Leggett GJ, Spencer ND, Williams NH. Photocatalytic nanolithography of self-assembled monolayers and proteins. ACS NANO 2013; 7:7610-8. [PMID: 23971891 PMCID: PMC4327559 DOI: 10.1021/nn402063b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 08/23/2013] [Indexed: 05/23/2023]
Abstract
Self-assembled monolayers of alkylthiolates on gold and alkylsilanes on silicon dioxide have been patterned photocatalytically on sub-100 nm length-scales using both apertured near-field and apertureless methods. Apertured lithography was carried out by means of an argon ion laser (364 nm) coupled to cantilever-type near-field probes with a thin film of titania deposited over the aperture. Apertureless lithography was carried out with a helium-cadmium laser (325 nm) to excite titanium-coated, contact-mode atomic force microscope (AFM) probes. This latter approach is readily implementable on any commercial AFM system. Photodegradation occurred in both cases through the localized photocatalytic degradation of the monolayer. For alkanethiols, degradation of one thiol exposed the bare substrate, enabling refunctionalization of the bare gold by a second, contrasting thiol. For alkylsilanes, degradation of the adsorbate molecule provided a facile means for protein patterning. Lines were written in a protein-resistant film formed by the adsorption of oligo(ethylene glycol)-functionalized trichlorosilanes on glass, leading to the formation of sub-100 nm adhesive, aldehyde-functionalized regions. These were derivatized with aminobutylnitrilotriacetic acid, and complexed with Ni(2+), enabling the binding of histidine-labeled green fluorescent protein, which yielded bright fluorescence from 70-nm-wide lines that could be imaged clearly in a confocal microscope.
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Affiliation(s)
- Ehtsham Ul-Haq
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
| | - Samson Patole
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Mark Moxey
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
| | - Esther Amstad
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
| | - Cvetelin Vasilev
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom
| | - C. Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Graham J. Leggett
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
| | - Nicholas D. Spencer
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
| | - Nicholas H. Williams
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
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9
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Pasternak S, Paz Y. On the Similarity and Dissimilarity between Photocatalytic Water Splitting and Photocatalytic Degradation of Pollutants. Chemphyschem 2013; 14:2059-70. [DOI: 10.1002/cphc.201300247] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Indexed: 11/10/2022]
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11
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Kisch H. Semiconductor photocatalysis--mechanistic and synthetic aspects. Angew Chem Int Ed Engl 2012; 52:812-47. [PMID: 23212748 DOI: 10.1002/anie.201201200] [Citation(s) in RCA: 416] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Indexed: 11/09/2022]
Abstract
Preceding work on photoelectrochemistry at semiconductor single-crystal electrodes has formed the basis for the tremendous growth in the three last decades in the field of photocatalysis at semiconductor powders. The reason for this is the unique ability of inorganic semiconductor surfaces to photocatalyze concerted reduction and oxidation reactions of a large variety of electron-donor and -acceptor substrates. Whereas great attention was paid to water splitting and the exhaustive aerobic degradation of pollutants, only a small amount of research also explored synthetic aspects. After introducing the basic mechanistic principles, standard experiments for the preparation and characterization of visible light active photocatalysts as well as the investigation of reaction mechanisms are discussed. Novel atom-economic C-C and C-N coupling reactions illustrate the relevance of semiconductor photocatalysis for organic synthesis, and demonstrate that the multidisciplinary field combines classical photochemistry with electrochemistry, solid-state chemistry, and heterogeneous catalysis.
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Affiliation(s)
- Horst Kisch
- Department Chemie und Pharmazie, Universität Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany.
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12
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Rajeshwar K, Chanmanee W. Bioinspired photocatalyst assemblies for environmental remediation. Electrochim Acta 2012. [DOI: 10.1016/j.electacta.2012.04.072] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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13
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Ochiai T, Fujishima A. Photoelectrochemical properties of TiO2 photocatalyst and its applications for environmental purification. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2012. [DOI: 10.1016/j.jphotochemrev.2012.07.001] [Citation(s) in RCA: 347] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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14
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Paz Y. Self-assembled monolayers and titanium dioxide: From surface patterning to potential applications. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2011; 2:845-61. [PMID: 22259769 PMCID: PMC3257511 DOI: 10.3762/bjnano.2.94] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 12/06/2011] [Indexed: 05/24/2023]
Abstract
The ability to control the properties of self-assembled monolayers (SAMs) attached to solid surfaces and the rare photocatalytic properties of titanium dioxide provide a rationale for the study of systems comprising both. Such systems can be realized in the form of SAMs grown on TiO(2) or, in a complementary manner, as TiO(2) grown on SAMs. Accordingly, the current status of knowledge regarding SAMs on TiO(2) is described. Photocatalytic phenomena that are of specific relevance to SAMs, such as remote degradation, and cases where SAMs were used to study photocatalytic phenomena, are discussed as well. Mastering of micro-patterning is a key issue en route to a successful assimilation of a variety of titanium dioxide based devices. Accordingly, particular attention is given to the description of a variety of methods and techniques aimed at utilizing the photocatalytic properties of titanium dioxide for patterning. Reports on a variety of applications are discussed. These examples, representing the areas of photovoltaics, microelectronics, microelectromechanics, photocatalysis, corrosion prevention and even biomedicine should be regarded as appetizers paving the way for further studies to be performed.
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Affiliation(s)
- Yaron Paz
- The Department of Chemical Engineering, The Russell-Berrie Institute of Nanotechnology and The Grand Water Research Institute, Technion, Haifa 32000, Israel
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15
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Kubacka A, Fernández-García M, Colón G. Advanced Nanoarchitectures for Solar Photocatalytic Applications. Chem Rev 2011; 112:1555-614. [DOI: 10.1021/cr100454n] [Citation(s) in RCA: 1901] [Impact Index Per Article: 146.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Anna Kubacka
- Instituto de Catálisis y Petroleoquímica, CSIC, C/Marie Curie 2, 28049-Madrid, Spain
| | | | - Gerardo Colón
- Instituto de Ciencia de Materiales de Sevilla, Centro Mixto CSIC-Universidad de Sevilla, C/Américo Vespucio, 49, 41092-Sevilla, Spain
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Tizazu G, El-Zubir O, Brueck SRJ, Lidzey DG, Leggett GJ, Lopez GP. Large area nanopatterning of alkylphosphonate self-assembled monolayers on titanium oxide surfaces by interferometric lithography. NANOSCALE 2011; 3:2511-2516. [PMID: 21431199 DOI: 10.1039/c0nr00994f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We demonstrate that interferometric lithography offers a fast, simple route to nanostructured self-assembled monolayers of alkylphosphonates on the native oxide of titanium. Exposure at 244 nm using a Lloyd's mirror interferometer caused the spatially periodic photocatalytic degradation of the adsorbates, yielding nanopatterns that extended over square centimetre areas. Exposed regions were re-functionalised by a second, contrasting alkylphosphonate, and the resulting patterns were used as templates for the assembly of molecular nanostructures; we demonstrate the fabrication of lines of polymer nanoparticles 46 nm wide. Nanopatterned monolayers were also employed as resists for etching of the metal film. Wires were formed with widths that could be varied between 46 and 126 nm simply by changing the exposure time. Square arrays of Ti dots as small as 35 nm (λ/7) were fabricated using two orthogonal exposures followed by wet etching.
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Affiliation(s)
- Getachew Tizazu
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, S3 7HF, UK
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Wagner S, Bloh J, Kasper C, Bahnemann D. Toxicological Issues of Nanoparticles Employed in Photocatalysis. ACTA ACUST UNITED AC 2011. [DOI: 10.1515/green.2011.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractA huge amount of different nanomaterials is nowadays on the market used for various specific applications. Some nanomaterials such as TiOHence these materials are used for many applications, e.g., for self-cleaning and antibacterial coatings on different surfaces and for the purification of wastewater where the cleaning can be induced by simple exposure to sunlight. Because of the frequent use of these nanoparticles it is important to investigate the life cycles of these nanostructured materials as well as their environmental impact and their toxicity to animals and humans.This review first gives a short overview about nanotechnology and nanotechnological products as well as about photocatalysis and semiconductors used in this field. We then discuss the need for a new technology named nanotoxicology and the problems occurring when investigating the toxic potential of nanomaterials as well as the life cycle of nanomaterials. Furthermore, we focus on the environmental impact of TiO
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Liu Y, Zhu A, Tian Y. Fluorescence imaging of hydroxyl radicals at superhydrophobic gold flower-like surface in photocatalytic system. Analyst 2011; 136:1106-8. [DOI: 10.1039/c0an00821d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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20
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Tizazu G, Adawi AM, Leggett GJ, Lidzey DG. Photopatterning, etching, and derivatization of self-assembled monolayers of phosphonic acids on the native oxide of titanium. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:10746-53. [PMID: 19606886 DOI: 10.1021/la901271c] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Electron-hole pair formation at titania surfaces leads to the formation of reactive species that degrade organic materials. Here, we describe the degradation of self-assembled monolayers of alkylphosphonic acids on the native oxide of titanium following exposure to UV light. The rate of degradation was found to decrease as the length of the adsorbate molecule increased. Increasing order in the monolayer, resulting from the enhanced dispersion forces between longer adsorbates, impedes the progress of oxygen-containing molecules to the oxide surface and slows the rate of oxidation. Rates of degradation on titanium oxide are substantially greater than rates of degradation on aluminum oxide because of the photocatalytic effect of the titanium oxide substrate. Micrometer-scale patterns may be fabricated readily using a UV laser in conjunction with a mask, and nanometer-scale patterns may be fabricated using a scanning near-field optical microscope coupled to a UV laser. Photodegraded adsorbates may be replaced by contrasting molecules to yield chemical contrast. Such patterned materials have been utilized to fabricate patterns from polymer nanoparticles. The resist character is switchable--at lower exposures, the monolayer behaves as a positive tone resist, but at higher exposures, it exhibits negative tone behavior. Patterned samples may also be utilized as resists for solution-phase etching of the underlying substrate.
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Affiliation(s)
- Getachew Tizazu
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K
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Khiterer M, Shea KJ. Spherical, monodisperse, functional bridged polysilsesquioxane nanoparticles. NANO LETTERS 2007; 7:2684-7. [PMID: 17655368 DOI: 10.1021/nl071087q] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A method for the synthesis of functional hybrid nanoparticles of uniform size is reported. 1,1'-bis[3-(trimethoxysilyl)propyl]-4,4'-bipyridinium iodide and N,N'-bis[(3-trimethoxysilyl)propyl]ethylenediamine bridged polysilsesquioxane spherical, monodisperse nanoparticles are prepared utilizing inverse water-in-oil polymerization methods where nanoparticle size can be influenced by adjusting the interfacial tension and monomer concentration. The former are electrochemically active and can be utilized in display devices. Both are polycationic and can be used as carriers for polyanions such as DNA and construction of layer-by-layer architectures.
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Affiliation(s)
- Mariya Khiterer
- Department of Chemistry, University of California, Irvine, 1102 Natural Sciences II, Irvine, California 92697-2025, USA
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Gamsey S, Miller A, Olmstead MM, Beavers CM, Hirayama LC, Pradhan S, Wessling RA, Singaram B. Boronic Acid-Based Bipyridinium Salts as Tunable Receptors for Monosaccharides and α-Hydroxycarboxylates. J Am Chem Soc 2007; 129:1278-86. [PMID: 17263411 DOI: 10.1021/ja066567i] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several novel diboronic acid-substituted bipyridinium salts were prepared and, using a fluorescent reporter dye, were tested for their ability to selectively bind various monosaccharides and alpha-hydroxycarboxylates in an aqueous medium. The fluorescence sensing mechanism relies on the formation of a ground-state charge-transfer complex between the dye and bipyridinium. An X-ray crystal structure of this complex is described herein. Glucose selectivity over fructose and galactose was achieved by designing the bipyridinium-based receptors to be capable of attaining a 1:1 receptor/substrate stoichiometry via cooperative diboronic acid binding.
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Affiliation(s)
- Soya Gamsey
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA
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Naoi K, Ohko Y, Tatsuma T. Switchable rewritability of Ag–TiO2nanocomposite films with multicolor photochromism. Chem Commun (Camb) 2005:1288-90. [PMID: 15742054 DOI: 10.1039/b416139d] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photochromism and rewritability of Ag-TiO2 films were deactivated by modification with thiols to make it possible to retain color images displayed on the films (for more than 3 days under white fluorescent lamps), while the deactivated properties were fully reactivated by UV-irradiation.
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Affiliation(s)
- Kenji Naoi
- Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
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Lee JP, Sung MM. A New Patterning Method Using Photocatalytic Lithography and Selective Atomic Layer Deposition. J Am Chem Soc 2004; 126:28-9. [PMID: 14709043 DOI: 10.1021/ja038769+] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a new patterning method using photocatalytic lithography of alkylsiloxane self-assembled monolayers and selective atomic layer deposition of thin films. The photocatalytic lithography is based on the fact that the decomposition rate of the alkylsiloxane monolayers in contact with TiO2 is much faster than that with SiO2 under UV irradiation in air. The photocatalytic lithography, using a quartz plate coated with patterned TiO2 thin films, was done to prepare patterned monolayers of the alkylsiloxane on Si substrates. A ZrO2 thin film was selectively deposited onto the monolayer-patterned Si substrate by atomic layer deposition.
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Affiliation(s)
- Jae P Lee
- Department of Chemistry, Kookmin University, Chongnung-dong, Songbuk-ku, Seoul 136-702, Korea
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