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Rauwel P, Rauwel E. Functional Nanomaterials for Optoelectronics and Photocatalysis. Nanomaterials (Basel) 2023; 13:2694. [PMID: 37836335 PMCID: PMC10574363 DOI: 10.3390/nano13192694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 09/26/2023] [Indexed: 10/15/2023]
Abstract
The present energy crisis has encouraged the use of energy-efficient devices and green energy sources [...].
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Affiliation(s)
- Protima Rauwel
- Institute of Forestry and Engineering Sciences, Estonian University of Life Sciences, 51006 Tartu, Estonia;
| | - Erwan Rauwel
- Institute of Forestry and Engineering Sciences, Estonian University of Life Sciences, 51006 Tartu, Estonia;
- Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, 51006 Tartu, Estonia
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2
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Nagpal K, Rauwel E, Ducroquet F, Gélard I, Rauwel P. Relevance of alcoholic solvents in the growth of ZnO nanoparticles and ZnO hierarchical nanorod structures on their optical and opto-electrical properties. Nanotechnology 2023; 34:485602. [PMID: 37651984 DOI: 10.1088/1361-6528/acf583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 08/31/2023] [Indexed: 09/02/2023]
Abstract
We report on the synthesis of ZnO nanoparticles and ZnO hierarchical nanorod structures using four different alcohols i.e. methanol, isopropanol, ethanol, and aqueous ethanol (70% alcohol, 30% water). The syntheses of the nanoparticles were carried out by non-aqueous and hydrothermal routes. In general, absolute alcohol allows a better control of the synthesis reaction and nanoparticles as small as 5 nm were obtained, confirmed by TEM. XPS analysis elucidated the chemical states that were correlated to the synthesis reaction. For the nanorod growth, these four alcohols were used as seeding solvents, followed by hydrothermal ZnO nanorod growth. Here, the seed layer tailored the nanorod diameters and surface defects, which were studied by SEM and photoluminescence spectroscopy. Subsequently, the ZnO nanorods were electrically characterized and exhibited persistent photoconductivity under UV irradiation of 365 nm. The differences in conductivity in dark and under UV irradiation were attributed to the size of the nanorods, defect states, semiconductor band bending and oxygen adsorption-desorption mechanisms. Parameters such as photoresponse and photosensitivity are also calculated in order to evaluate their applicability in UV sensors. This work demonstrates optimization of the physical, chemical, electrical and optical properties of both ZnO nanostructures via the use of alcoholic solvents.
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Affiliation(s)
- Keshav Nagpal
- Institute of Forestry and Engineering, Estonian University of Life Science, Kreutzwaldi 56/1, Tartu, Estonia
| | - Erwan Rauwel
- Institute of Forestry and Engineering, Estonian University of Life Science, Kreutzwaldi 56/1, Tartu, Estonia
- Institute of Veterinary Medicine and Animal Science, Estonian University of Life Science, Kreutzwaldi 62, Tartu, Estonia
| | | | - Isabelle Gélard
- Université Grenoble Alpes, CNRS, Grenoble INP, LMGP, F-38000 Grenoble, France
| | - Protima Rauwel
- Institute of Forestry and Engineering, Estonian University of Life Science, Kreutzwaldi 56/1, Tartu, Estonia
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Hendrix Y, Rauwel E, Nagpal K, Haddad R, Estephan E, Boissière C, Rauwel P. Revealing the Dependency of Dye Adsorption and Photocatalytic Activity of ZnO Nanoparticles on Their Morphology and Defect States. Nanomaterials (Basel) 2023; 13:1998. [PMID: 37446514 DOI: 10.3390/nano13131998] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 06/28/2023] [Accepted: 06/29/2023] [Indexed: 07/15/2023]
Abstract
ZnO is an effective photocatalyst applied to the degradation of organic dyes in aqueous media. In this study, the UV-light and sunlight-driven photocatalytic activities of ZnO nanoparticles are evaluated. A handheld Lovibond photometer was purposefully calibrated in order to monitor the dye removal in outdoor conditions. The effect of ZnO defect states, i.e., the presence of zinc and oxygen defects on the photocatalytic activity was probed for two types of dyes: fuchsin and methylene blue. Three morphologies of ZnO nanoparticles were deliberately selected, i.e., spherical, facetted and a mix of spherical and facetted, ascertained via transmission electron microscopy. Aqueous and non-aqueous sol-gel routes were applied to their synthesis in order to tailor their size, morphology and defect states. Raman spectroscopy demonstrated that the spherical nanoparticles contained a high amount of oxygen vacancies and zinc interstitials. Photoluminescence spectroscopy revealed that the facetted nanoparticles harbored zinc vacancies in addition to oxygen vacancies. A mechanism for dye degradation based on the possible surface defects in facetted nanoparticles is proposed in this work. The reusability of these nanoparticles for five cycles of dye degradation was also analyzed. More specifically, facetted ZnO nanoparticles tend to exhibit higher efficiencies and reusability than spherical nanoparticles.
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Affiliation(s)
- Yuri Hendrix
- Institute of Forestry and Engineering Sciences, Estonian University of Life Sciences, 51014 Tartu, Estonia
| | - Erwan Rauwel
- Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, 51006 Tartu, Estonia
| | - Keshav Nagpal
- Institute of Forestry and Engineering Sciences, Estonian University of Life Sciences, 51014 Tartu, Estonia
| | - Ryma Haddad
- Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), Collège de France, CNRS, Sorbonne Université, 75005 Paris, France
| | - Elias Estephan
- Laboratoire Bioinginirie et Nanoscience (LBN), University of Montpellier, 34193 Montpellier, France
| | - Cédric Boissière
- Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), Collège de France, CNRS, Sorbonne Université, 75005 Paris, France
| | - Protima Rauwel
- Institute of Forestry and Engineering Sciences, Estonian University of Life Sciences, 51014 Tartu, Estonia
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Ponte R, Rauwel E, Rauwel P. Tailoring SnO 2 Defect States and Structure: Reviewing Bottom-Up Approaches to Control Size, Morphology, Electronic and Electrochemical Properties for Application in Batteries. Materials (Basel) 2023; 16:4339. [PMID: 37374523 DOI: 10.3390/ma16124339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/05/2023] [Accepted: 06/09/2023] [Indexed: 06/29/2023]
Abstract
Tin oxide (SnO2) is a versatile n-type semiconductor with a wide bandgap of 3.6 eV that varies as a function of its polymorph, i.e., rutile, cubic or orthorhombic. In this review, we survey the crystal and electronic structures, bandgap and defect states of SnO2. Subsequently, the significance of the defect states on the optical properties of SnO2 is overviewed. Furthermore, we examine the influence of growth methods on the morphology and phase stabilization of SnO2 for both thin-film deposition and nanoparticle synthesis. In general, thin-film growth techniques allow the stabilization of high-pressure SnO2 phases via substrate-induced strain or doping. On the other hand, sol-gel synthesis allows precipitating rutile-SnO2 nanostructures with high specific surfaces. These nanostructures display interesting electrochemical properties that are systematically examined in terms of their applicability to Li-ion battery anodes. Finally, the outlook provides the perspectives of SnO2 as a candidate material for Li-ion batteries, while addressing its sustainability.
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Affiliation(s)
- Reynald Ponte
- Institute of Forestry and Engineering, Estonian University of Life Sciences, 51006 Tartu, Estonia
| | - Erwan Rauwel
- Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, 51006 Tartu, Estonia
| | - Protima Rauwel
- Institute of Forestry and Engineering, Estonian University of Life Sciences, 51006 Tartu, Estonia
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Paredes P, Rauwel E, Wragg DS, Rapenne L, Estephan E, Volobujeva O, Rauwel P. Sunlight-Driven Photocatalytic Degradation of Methylene Blue with Facile One-Step Synthesized Cu-Cu 2O-Cu 3N Nanoparticle Mixtures. Nanomaterials (Basel) 2023; 13:1311. [PMID: 37110901 PMCID: PMC10144494 DOI: 10.3390/nano13081311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 04/03/2023] [Accepted: 04/06/2023] [Indexed: 06/19/2023]
Abstract
Sunlight-driven photocatalytic degradation is an effective and eco-friendly technology for the removal of organic pollutants from contaminated water. Herein, we describe the one-step synthesis of Cu-Cu2O-Cu3N nanoparticle mixtures using a novel non-aqueous, sol-gel route and their application in the solar-driven photocatalytic degradation of methylene blue. The crystalline structure and morphology were investigated with XRD, SEM and TEM. The optical properties of the as-prepared photocatalysts were investigated with Raman, FTIR, UV-Vis and photoluminescence spectroscopies. The influence of the phase proportions of Cu, Cu2O and Cu3N in the nanoparticle mixtures on the photocatalytic activity was also investigated. Overall, the sample containing the highest quantity of Cu3N exhibits the highest photocatalytic degradation efficiency (95%). This enhancement is attributed to factors such as absorption range broadening, increased specific surface of the photocatalysts and the downward band bending in the p-type semiconductors, i.e., Cu3N and Cu2O. Two different catalytic dosages were studied, i.e., 5 mg and 10 mg. The higher catalytic dosage exhibited lower photocatalytic degradation efficiency owing to the increase in the turbidity of the solution.
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Affiliation(s)
- Patricio Paredes
- Institute of Forestry and Engineering Sciences, Estonian University of Life Sciences, Kreutzwaldi 56/1, 51014 Tartu, Estonia; (P.P.); (E.R.)
| | - Erwan Rauwel
- Institute of Forestry and Engineering Sciences, Estonian University of Life Sciences, Kreutzwaldi 56/1, 51014 Tartu, Estonia; (P.P.); (E.R.)
| | - David S. Wragg
- Department of Chemistry and SMN, University of Oslo, 0315 Oslo, Norway;
| | - Laetitia Rapenne
- Grenoble Institute of Engineering, LMGP, University Grenoble Alpes, CNRS, F-38000 Grenoble, France;
| | - Elias Estephan
- Laboratory of Bioengineering and Biosciences, LBN, Univ Montpellier, 34193 Montpellier, France
| | - Olga Volobujeva
- Institute of Materials and Environmental Technology, Tallinn University of Technology, 19086 Tallinn, Estonia;
| | - Protima Rauwel
- Institute of Forestry and Engineering Sciences, Estonian University of Life Sciences, Kreutzwaldi 56/1, 51014 Tartu, Estonia; (P.P.); (E.R.)
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Nagpal K, Rauwel E, Estephan E, Soares MR, Rauwel P. Significance of Hydroxyl Groups on the Optical Properties of ZnO Nanoparticles Combined with CNT and PEDOT:PSS. Nanomaterials (Basel) 2022; 12:3546. [PMID: 36234673 PMCID: PMC9565678 DOI: 10.3390/nano12193546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/07/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
We report on the synthesis of ZnO nanoparticles and their hybrids consisting of carbon nanotubes (CNT) and polystyrene sulfonate (PEDOT:PSS). A non-aqueous sol-gel route along with hydrated and anhydrous acetate precursors were selected for their syntheses. Transmission electron microscopy (TEM) studies revealed their spherical shape with an average size of 5 nm. TEM also confirmed the successful synthesis of ZnO-CNT and ZnO-PEDOT:PSS hybrid nanocomposites. In fact, the choice of precursors has a direct influence on the chemical and optical properties of the ZnO-based nanomaterials. The ZnO nanoparticles prepared with anhydrous acetate precursor contained a high amount of oxygen vacancies, which tend to degrade the polymer macromolecule, as confirmed from X-ray photoelectron spectroscopy and Raman spectroscopy. Furthermore, a relative increase in hydroxyl functional groups in the ZnO-CNT samples was observed. These functional groups were instrumental in the successful decoration of CNT and in producing the defect-related photoluminescence emission in ZnO-CNT.
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Affiliation(s)
- Keshav Nagpal
- Institute of Forestry and Engineering, Estonian University of Life Sciences, 51014 Tartu, Estonia
| | - Erwan Rauwel
- Institute of Forestry and Engineering, Estonian University of Life Sciences, 51014 Tartu, Estonia
| | - Elias Estephan
- LBN, University of Montpellier, 34193 Montpellier, France
| | | | - Protima Rauwel
- Institute of Forestry and Engineering, Estonian University of Life Sciences, 51014 Tartu, Estonia
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Nagpal K, Rauwel E, Ducroquet F, Rauwel P. Assessment of the optical and electrical properties of light-emitting diodes containing carbon-based nanostructures and plasmonic nanoparticles: a review. Beilstein J Nanotechnol 2021; 12:1078-1092. [PMID: 34631340 PMCID: PMC8474067 DOI: 10.3762/bjnano.12.80] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
Light-emitting diodes (LED) are widely employed in display applications and lighting systems. Further research on LED that incorporates carbon nanostructures and metal nanoparticles exhibiting surface plasmon resonance has demonstrated a significant improvement in device performance. These devices offer lower turn-on voltages, higher external quantum efficiencies, and luminance. De facto, plasmonic nanoparticles, such as Au and Ag have boosted the luminance of red, green, and blue emissions. When combined with carbon nanostructures they additionally offer new possibilities towards lightweight and flexible devices with better thermal management. This review surveys the diverse possibilities to combine various inorganic, organic, and carbon nanostructures along with plasmonic nanoparticles. Such combinations would allow an enhancement in the overall properties of LED.
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Affiliation(s)
- Keshav Nagpal
- Institute of Technology, Estonian University of Life Sciences, Kreutzwaldi 56/1, 51014 Tartu, Estonia
| | - Erwan Rauwel
- Institute of Technology, Estonian University of Life Sciences, Kreutzwaldi 56/1, 51014 Tartu, Estonia
| | | | - Protima Rauwel
- Institute of Technology, Estonian University of Life Sciences, Kreutzwaldi 56/1, 51014 Tartu, Estonia
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Rauwel P, Galeckas A, Rauwel E. Enhancing the UV Emission in ZnO-CNT Hybrid Nanostructures via the Surface Plasmon Resonance of Ag Nanoparticles. Nanomaterials (Basel) 2021; 11:452. [PMID: 33579049 PMCID: PMC7916755 DOI: 10.3390/nano11020452] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/04/2021] [Accepted: 02/06/2021] [Indexed: 12/16/2022]
Abstract
The crystal quality and surface states are two major factors that determine optical properties of ZnO nanoparticles (NPs) synthesized through nonaqueous sol-gel routes, and both are strongly dependent on the growth conditions. In this work, we investigate the influence of the different growth temperatures (240 and 300 °C) on the morphology, structural and crystal properties of ZnO NP. The effects of conjoining ZnO NP with carbon nanotubes (CNT) and the role of surface states in such a hybrid nanostructure are studied by optical emission and absorption spectroscopy. We demonstrate that depending on the synthesis conditions, activation or passivation of certain surface states may occur. Next, silver nanoparticles are incorporated into ZnO-CNT nanostructures to explore the plasmon-exciton coupling effect. The observed enhanced excitonic and suppressed defect-related emissions along with blue-shifted optical band gap suggest an intricate interaction of Burstein-Moss, surface plasmon resonance and surface band-bending effects behind the optical phenomena in hybrid ZnO-CNT-Ag nanocomposites.
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Affiliation(s)
- Protima Rauwel
- Institute of Technology, Estonian University of Life Sciences, 51014 Tartu, Estonia;
| | - Augustinas Galeckas
- Department of Physics, University of Oslo, P.O. Box 1048 Blindern, 0316 Oslo, Norway;
| | - Erwan Rauwel
- Institute of Technology, Estonian University of Life Sciences, 51014 Tartu, Estonia;
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Xie R, Batchelor‐McAuley C, Rauwel E, Rauwel P, Compton RG. Electrochemical Characterisation of Co@Co(OH)
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Core‐Shell Nanoparticles and their Aggregation in Solution. ChemElectroChem 2020. [DOI: 10.1002/celc.202001199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Ruo‐Chen Xie
- Department of Chemistry Physical and Theoretical Chemistry Laboratory University of Oxford South Parks Road Oxford OX1 3QZ UK
| | - Christopher Batchelor‐McAuley
- Department of Chemistry Physical and Theoretical Chemistry Laboratory University of Oxford South Parks Road Oxford OX1 3QZ UK
| | - Erwan Rauwel
- Institute of Technology Estonian University of Life Sciences Kreutzwaldi 1 51014 T artu Estonia
- School of Engineering Tallinn University of Technology Akadeemia tee 15 12618 Tallinn Estonia
| | - Protima Rauwel
- Institute of Technology Estonian University of Life Sciences Kreutzwaldi 1 51014 T artu Estonia
| | - Richard G. Compton
- Department of Chemistry Physical and Theoretical Chemistry Laboratory University of Oxford South Parks Road Oxford OX1 3QZ UK
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Rauwel E, Al-Arag S, Salehi H, Amorim CO, Cuisinier F, Guha M, Rosario MS, Rauwel P. Assessing Cobalt Metal Nanoparticles Uptake by Cancer Cells Using Live Raman Spectroscopy. Int J Nanomedicine 2020; 15:7051-7062. [PMID: 33061367 PMCID: PMC7522600 DOI: 10.2147/ijn.s258060] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 07/08/2020] [Indexed: 11/26/2022] Open
Abstract
Purpose Nanotechnology applied to cancer treatment is a growing area of research in nanomedicine with magnetic nanoparticle-mediated anti-cancer drug delivery systems offering least possible side effects. To that end, both structural and chemical properties of commercial cobalt metal nanoparticles were studied using label-free confocal Raman spectroscopy. Materials and Methods Crystal structure and morphology of cobalt nanoparticles were studied by XRD and TEM. Magnetic properties were studied with SQUID and PPMS. Confocal Raman microscopy has high spatial resolution and compositional sensitivity. It, therefore, serves as a label-free tool to trace nanoparticles within cells and investigate the interaction between coating-free cobalt metal nanoparticles and cancer cells. The toxicity of cobalt nanoparticles against human cells was assessed by MTT assay. Results Superparamagnetic Co metal nanoparticle uptake by MCF7 and HCT116 cancer cells and DPSC mesenchymal stem cells was investigated by confocal Raman microscopy. The Raman nanoparticle signature also allowed accurate detection of the nanoparticle within the cell without labelling. A rapid uptake of the cobalt nanoparticles followed by rapid apoptosis was observed. Their low cytotoxicity, assessed by means of MTT assay against human embryonic kidney (HEK) cells, makes them promising candidates for the development of targeted therapies. Moreover, under a laser irradiation of 20mW with a wavelength of 532nm, it is possible to bring about local heating leading to combustion of the cobalt metal nanoparticles within cells, whereupon opening new routes for cancer phototherapy. Conclusion Label-free confocal Raman spectroscopy enables accurately localizing the Co metal nanoparticles in cellular environments. The interaction between the surfactant-free cobalt metal nanoparticles and cancer cells was investigated. The facile endocytosis in cancer cells shows that these nanoparticles have potential in engendering their apoptosis. This preliminary study demonstrates the feasibility and relevance of cobalt nanomaterials for applications in nanomedicine such as phototherapy, hyperthermia or stem cell delivery.
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Affiliation(s)
- Erwan Rauwel
- Institute of Technology, Estonian University of Life Sciences, Tartu, Estonia
| | | | | | - Carlos O Amorim
- Dpt. Of Physics & CICECO - Aveiro Institute of Materials, University of Aveiro, Aveiro, Portugal
| | | | - Mithu Guha
- Dpt. Of General & Molecular Pathology, Faculty of Medicine, University of Tartu, Tartu, Estonia
| | - Maria S Rosario
- CICECO - Aveiro Institute of Materials, University of Aveiro, Aveiro, Portugal
| | - Protima Rauwel
- Institute of Technology, Estonian University of Life Sciences, Tartu, Estonia
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Küünal S, Visnapuu M, Volubujeva O, Soares Rosario M, Rauwel P, Rauwel E. Optimisation of plant mediated synthesis of silver nanoparticles by common weed Plantago major and their antimicrobial properties. ACTA ACUST UNITED AC 2019. [DOI: 10.1088/1757-899x/613/1/012003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Rauwel P, Rauwel E. Towards the Extraction of Radioactive Cesium-137 from Water via Graphene/CNT and Nanostructured Prussian Blue Hybrid Nanocomposites: A Review. Nanomaterials (Basel) 2019; 9:E682. [PMID: 31052518 PMCID: PMC6566935 DOI: 10.3390/nano9050682] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 04/23/2019] [Accepted: 04/24/2019] [Indexed: 11/16/2022]
Abstract
Cesium is a radioactive fission product generated in nuclear power plants and is disposed of as liquid waste. The recent catastrophe at the Fukushima Daiichi nuclear plant in Japan has increased the 137Cs and 134Cs concentrations in air, soil and water to lethal levels. 137Cs has a half-life of 30.4 years, while the half-life of 134Cs is around two years, therefore the formers' detrimental effects linger for a longer period. In addition, cesium is easily transported through water bodies making water contamination an urgent issue to address. Presently, efficient water remediation methods towards the extraction of 137Cs are being studied. Prussian blue (PB) and its analogs have shown very high efficiencies in the capture of 137Cs+ ions. In addition, combining them with magnetic nanoparticles such as Fe3O4 allows their recovery via magnetic extraction once exhausted. Graphene and carbon nanotubes (CNT) are the new generation carbon allotropes that possess high specific surface areas. Moreover, the possibility to functionalize them with organic or inorganic materials opens new avenues in water treatment. The combination of PB-CNT/Graphene has shown enhanced 137Cs+ extraction and their possible applications as membranes can be envisaged. This review will survey these nanocomposites, their efficiency in 137Cs+ extraction, their possible toxicity, and prospects in large-scale water remediation and succinctly survey other new developments in 137Cs+ extraction.
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Affiliation(s)
- Protima Rauwel
- Institute of Technology, Estonian University of Life Sciences, Kreutzwaldi 56/1, 51014 Tartu, Estonia.
| | - Erwan Rauwel
- Institute of Technology, Estonian University of Life Sciences, Kreutzwaldi 56/1, 51014 Tartu, Estonia.
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Praats R, Kruusenberg I, Käärik M, Joost U, Aruväli J, Paiste P, Saar R, Rauwel P, Kook M, Leis J, Zagal JH, Tammeveski K. Electroreduction of oxygen in alkaline solution on iron phthalocyanine modified carbide-derived carbons. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2019.01.062] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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14
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Rauwel E, Simón-Gracia L, Guha M, Rauwel P, Kuunal S, Wragg D. Silver metal nanoparticles study for biomedical and green house applications. ACTA ACUST UNITED AC 2017. [DOI: 10.1088/1757-899x/175/1/012011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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15
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Rauwel P, Galeckas A, Salumaa M, Ducroquet F, Rauwel E. Photocurrent generation in carbon nanotube/cubic-phase HfO2 nanoparticle hybrid nanocomposites. Beilstein J Nanotechnol 2016; 7:1075-85. [PMID: 27547626 PMCID: PMC4979767 DOI: 10.3762/bjnano.7.101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 07/06/2016] [Indexed: 06/06/2023]
Abstract
A hybrid material consisting of nonfunctionalized multiwall carbon nanotubes (MWCNTs) and cubic-phase HfO2 nanoparticles (NPs) with an average diameter of 2.6 nm has been synthesized. Free standing HfO2 NPs present unusual optical properties and a strong photoluminescence emission in the visible region, originating from surface defects. Transmission electron microscopy studies show that these NPs decorate the MWCNTs on topological defect sites. The electronic structure of the C K-edge in the nanocomposites was probed by electron energy loss spectroscopy, highlighting the key role of the MWCNT growth defects in anchoring HfO2 NPs. A combined optical emission and absorption spectroscopy approach illustrated that, in contrast to HfO2 NPs, the metallic MWCNTs do not emit light but instead expose their discrete electronic structure in the absorption spectra. The hybrid material manifests characteristic absorption features with a gradual merger of the MWCNT π-plasmon resonance band with the intrinsic defect band and fundamental edge of HfO2. The photoluminescence of the nanocomposites indicates features attributed to combined effects of charge desaturation of HfO2 surface states and charge transfer to the MWCNTs with an overall reduction of radiative recombination. Finally, photocurrent generation under UV-vis illumination suggests that a HfO2 NP/MWCNT hybrid system can be used as a flexible nanodevice for light harvesting applications.
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Affiliation(s)
- Protima Rauwel
- Institute of Physics, University of Tartu, Ravila 14c, 51014 Tartu, Estonia
- Department of Physics, University of Oslo. P.O. Box 1048 Blindern, 0316 Oslo, Norway
| | - Augustinas Galeckas
- Department of Physics, University of Oslo. P.O. Box 1048 Blindern, 0316 Oslo, Norway
| | - Martin Salumaa
- Tartu College, Tallinn University of Technology, Puiestee 78, 51008 Tartu, Estonia
| | - Frédérique Ducroquet
- IMEP-LAHC, CNRS, Université de Grenoble-Alpes, Minatec campus, 38016 Grenoble, France
| | - Erwan Rauwel
- Tartu College, Tallinn University of Technology, Puiestee 78, 51008 Tartu, Estonia
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Kelp G, Tätte T, Pikker S, Mändar H, Rozhin AG, Rauwel P, Vanetsev AS, Gerst A, Merisalu M, Mäeorg U, Natali M, Persson I, Kessler VG. Self-assembled SnO2 micro- and nanosphere-based gas sensor thick films from an alkoxide-derived high purity aqueous colloid precursor. Nanoscale 2016; 8:7056-7067. [PMID: 26960813 DOI: 10.1039/c5nr07942j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Tin oxide is considered to be one of the most promising semiconductor oxide materials for use as a gas sensor. However, a simple route for the controllable build-up of nanostructured, sufficiently pure and hierarchical SnO2 structures for gas sensor applications is still a challenge. In the current work, an aqueous SnO2 nanoparticulate precursor sol, which is free of organic contaminants and sorbed ions and is fully stable over time, was prepared in a highly reproducible manner from an alkoxide Sn(OR)4 just by mixing it with a large excess of pure neutral water. The precursor is formed as a separate liquid phase. The structure and purity of the precursor is revealed using XRD, SAXS, EXAFS, HRTEM imaging, FTIR, and XRF analysis. An unconventional approach for the estimation of the particle size based on the quantification of the Sn-Sn contacts in the structure was developed using EXAFS spectroscopy and verified using HRTEM. To construct sensors with a hierarchical 3D structure, we employed an unusual emulsification technique not involving any additives or surfactants, using simply the extraction of the liquid phase, water, with the help of dry butanol under ambient conditions. The originally generated crystalline but yet highly reactive nanoparticles form relatively uniform spheres through self-assembly and solidify instantly. The spheres floating in butanol were left to deposit on the surface of quartz plates bearing sputtered gold electrodes, producing ready-for-use gas sensors in the form of ca. 50 μm thick sphere-based-films. The films were dried for 24 h and calcined at 300 °C in air before use. The gas sensitivity of the structures was tested in the temperature range of 150-400 °C. The materials showed a very quickly emerging and reversible (20-30 times) increase in electrical conductivity as a response to exposure to air containing 100 ppm of H2 or CO and short (10 s) recovery times when the gas flow was stopped.
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Affiliation(s)
- G Kelp
- Institute of Physics, University of Tartu, Ravila 14C, 50411, Tartu, Estonia. and Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - T Tätte
- Institute of Physics, University of Tartu, Ravila 14C, 50411, Tartu, Estonia.
| | - S Pikker
- Institute of Physics, University of Tartu, Ravila 14C, 50411, Tartu, Estonia.
| | - H Mändar
- Institute of Physics, University of Tartu, Ravila 14C, 50411, Tartu, Estonia.
| | - A G Rozhin
- Aston University, Aston Triangle, Birmingham, B4 7ET, UK
| | - P Rauwel
- Department of Physics, Centre for Materials Science and Nanotechnology, University of Oslo, PO Box 1048 Blindern, N-0316 Oslo, Norway
| | - A S Vanetsev
- Institute of Physics, University of Tartu, Ravila 14C, 50411, Tartu, Estonia. and General Physics Institute RAS, 38 Vavilov str., 119991, Moscow, Russia
| | - A Gerst
- Institute of Physics, University of Tartu, Ravila 14C, 50411, Tartu, Estonia.
| | - M Merisalu
- Institute of Physics, University of Tartu, Ravila 14C, 50411, Tartu, Estonia.
| | - U Mäeorg
- Institute of Chemistry, University of Tartu, Ravila 14A, 50441, Tartu, Estonia
| | - M Natali
- ICIS-CNR, CorsoStatiUniti 4, 35127 Padova, Italy
| | - I Persson
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-756 51 Uppsala, Sweden
| | - V G Kessler
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-756 51 Uppsala, Sweden
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Türk KK, Kruusenberg I, Mondal J, Rauwel P, Kozlova J, Matisen L, Sammelselg V, Tammeveski K. Oxygen electroreduction on MN4-macrocycle modified graphene/multi-walled carbon nanotube composites. J Electroanal Chem (Lausanne) 2015. [DOI: 10.1016/j.jelechem.2015.08.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Vikkisk M, Kruusenberg I, Ratso S, Joost U, Shulga E, Kink I, Rauwel P, Tammeveski K. Enhanced electrocatalytic activity of nitrogen-doped multi-walled carbon nanotubes towards the oxygen reduction reaction in alkaline media. RSC Adv 2015. [DOI: 10.1039/c5ra08818f] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Nitrogen-doped carbon nanotube materials derived from dicyandiamide and cyanamide are highly active electrocatalysts for oxygen reduction reaction in alkaline media.
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Affiliation(s)
| | | | - Sander Ratso
- Institute of Chemistry
- University of Tartu
- Ravila 14a
- Estonia
| | - Urmas Joost
- Institute of Physics
- University of Tartu
- Ravila 14c
- Estonia
| | - Eugene Shulga
- Institute of Physics
- University of Tartu
- Ravila 14c
- Estonia
| | - Ilmar Kink
- Institute of Physics
- University of Tartu
- Ravila 14c
- Estonia
| | - Protima Rauwel
- Institute of Physics
- University of Tartu
- Ravila 14c
- Estonia
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19
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Tätte T, Part M, Talviste R, Hanschmidt K, Utt K, Mäeorg U, Jõgi I, Kiisk V, Mändar H, Nurk G, Rauwel P. Yttria stabilized zirconia microtubes for microfluidics under extreme conditions. RSC Adv 2014. [DOI: 10.1039/c4ra00621f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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20
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Rauwel E, Nilsen O, Rauwel P, Walmsley JC, Frogner HB, Rytter E, Fjellvåg H. Oxide Coating of Alumina Nanoporous Structure Using ALD to Produce Highly Porous Spinel. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/cvde.201207005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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21
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Iwu KO, Galeckas A, Rauwel P, Kuznetsov AY, Norby T. One-dimensional WO3 and its hydrate: One-step synthesis, structural and spectroscopic characterization. J SOLID STATE CHEM 2012. [DOI: 10.1016/j.jssc.2011.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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22
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Pereira AS, Rauwel P, Martins MA, Trindade T. From single-molecule precursors to hybrid ZnS nanostructures. J Nanosci Nanotechnol 2010; 10:2768-2775. [PMID: 20355499 DOI: 10.1166/jnn.2010.1403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A series of coordination compounds containing [Zn(amine)]2+ cationic complexes and alkyldithiocarbamates (RR'dtc-), as counter anions, are reported here: [Zn(amine)x][RR'dtc]2, where amine = ethylenediamine (en), diethylenetriamine (dien), 1,2-diaminopropane (dap) and, R,R' = ethyl (Et); butyl (Bu) and methyl (Me), hexyl (Hex). Hybrid nanoplates composed of hexagonal-ZnS nanoparticles and organic components were obtained after solution phase thermolysis of such precursors in oleylamine. These hybrid materials show quantum confinement effects in their optical spectra and convert into cubic-ZnS after further thermal treatment.
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Affiliation(s)
- Angela S Pereira
- Department of Chemistry and CICECO, University of Aveiro, 3810-193 Aveiro, Portugal
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Toberer ES, Rauwel P, Gariel S, Taftø J, Jeffrey Snyder G. Composition and the thermoelectric performance of β-Zn4Sb3. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/c0jm02011g] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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24
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Rauwel E, Clavel G, Willinger MG, Rauwel P, Pinna N. Non-Aqueous Routes to Metal Oxide Thin Films by Atomic Layer Deposition. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200705550] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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25
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Rauwel E, Clavel G, Willinger MG, Rauwel P, Pinna N. Non-Aqueous Routes to Metal Oxide Thin Films by Atomic Layer Deposition. Angew Chem Int Ed Engl 2008; 47:3592-5. [DOI: 10.1002/anie.200705550] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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26
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Neves MC, Martins MA, Soares-Santos PCR, Rauwel P, Ferreira RAS, Monteiro T, Carlos LD, Trindade T. Photoluminescent, transparent and flexible di-ureasil hybrids containing CdSe/ZnS quantum dots. Nanotechnology 2008; 19:155601. [PMID: 21825615 DOI: 10.1088/0957-4484/19/15/155601] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We describe, in this paper, the sol-gel synthesis of di-ureasil based nanocomposites prepared in situ in the presence of organically capped CdSe quantum dots (QDs) or CdSe QDs which have been coated with a ZnS shell. For the latter a new chemical route to coat the CdSe QDs with ZnS shells was investigated and is now reported. The QDs became well dispersed in the final nanocomposites, whose microstructural homogeneity was evaluated by atomic force microscopy (AFM) and transmission electron microscopy (TEM) analyses. In order to understand the optical behaviour of di-ureasil containing QDs, a detailed photoluminescent study was undertaken for a selected particle size distribution of ZnS coated CdSe QDs (d∼4.5 nm). Emission quantum yields up to 0.11 were measured in the final nanocomposites that present a huge (between 3 and 6 orders of magnitude) increase in the lifetime of the QDs (relative to that of isolated ones), as a result of energy transfer occurring between the intimately mixed di-ureasil host and the QDs.
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Affiliation(s)
- Márcia C Neves
- Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro, Portugal
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Pereira AS, Rauwel P, Reis MS, Oliveira Silva NJ, Barros-Timmons A, Trindade T. Polymer encapsulation effects on the magnetism of EuS nanocrystals. ACTA ACUST UNITED AC 2008. [DOI: 10.1039/b806499g] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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