Parametric Study on Dimensional Control of ZnO Nanowalls and Nanowires by Electrochemical Deposition

A simple electrochemical deposition technique is used to synthesize both two-dimensional (nanowall) and one-dimensional (nanowire) ZnO nanostructures on indium-tin-oxide-coated glass substrates at 70°C. By fine-tuning the deposition conditions, particularly the initial Zn(NO3)2·6H2O electrolyte concentration, the mean ledge thickness of the nanowalls (50–100 nm) and the average diameter of the nanowires (50–120 nm) can be easily varied. The KCl supporting electrolyte used in the electrodeposition also has a pronounced effect on the formation of the nanowalls, due to the adsorption of Cl− ions on the preferred (0001) growth plane of ZnO and thereby redirecting growth on the (100) and (20) planes. Furthermore, evolution from the formation of ZnO nanowalls to formation of nanowires is observed as the KCl concentration is reduced in the electrolyte. The crystalline properties and growth directions of the as-synthesized ZnO nanostructures are studied in details by glancing-incidence X-ray diffraction and transmission electron microscopy

Reductive electrosynthesis of crystalline metal-organic frameworks

Electroreduction of oxoanions affords hydroxide equivalents that induce selective deposition of crystalline metal–organic frameworks (MOFs) on conductive surfaces. The method is illustrated by cathodic electrodeposition of Zn[subscript 4]O(BDC)[subscript 3] (MOF-5; BDC = 1,4-benzenedicarboxylate), which is deposited at room temperature in only 15 min under cathodic potential. Although many crystalline phases are known in the Zn[superscript 2+]/BDCsuperscript 2–] system, MOF-5 is the only observed crystalline MOF phase under these conditions. This fast and mild method of synthesizing MOFs is amenable to direct surface functionalization and could impact applications requiring conformal coatings of microporous MOFs, such as gas separation membranes and electrochemical sensors.Massachusetts Institute of Technology. Energy Initiative (Seed Fund Program)National Science Foundation (U.S.) (Grant CHE-9808061)National Science Foundation (U.S.) (Grant DBI-9729592)National Science Foundation (U.S.) (Grant DMR- 0819762

Nucleant layer effect on nanocolumnar ZnO films grown by electrodeposition

Different ZnO nanostructured films were electrochemically grown, using an aqueous solution based on ZnCl2, on three types of transparent conductive oxides grow on commercial ITO (In2O3:Sn)-covered glass substrates: (1) ZnO prepared by spin coating, (2) ZnO prepared by direct current magnetron sputtering, and (3) commercial ITO-covered glass substrates. Although thin, these primary oxide layers play an important role on the properties of the nanostructured films grown on top of them. Additionally, these primary oxide layers prevent direct hole combination when used in optoelectronic devices. Structural and optical characterizations were carried out by scanning electron microscopy, atomic force microscopy, and optical transmission spectroscopy. We show that the properties of the ZnO nanostructured films depend strongly on the type of primary oxide-covered substrate used. Previous studies on different electrodeposition methods for nucleation and growth are considered in the final discussion.We thank Prof. A. Segura of the Universitat de Valencia for the facilities with the sputtering equipment. This work was supported by the project PROMETEO/2009/074 from the Generalitat Valenciana.Reyes Tolosa, MD.; Damonte, LC.; Brine, H.; Bolink, HJ.; Hernández Fenollosa, MDLÁ. (2013). Nucleant layer effect on nanocolumnar ZnO films grown by electrodeposition. Nanoscale Research Letters. 8:135-144. https://doi.org/10.1186/1556-276X-8-135S1351448Franklin JB, Zou B, Petrov P, McComb DW, Ryanand MP, McLachlan MA,J: Optimised pulsed laser deposition of ZnO thin films on transparent conducting substrates. Mater Chem 2011, 21: 8178–8182. 10.1039/c1jm10658aJaroslav B, Andrej V, Marie N, Šuttab P, Miroslav M, František U: Cryogenic pulsed laser deposition of ZnO. Vacuum 2012, 86(6):684–688. 10.1016/j.vacuum.2011.07.033Jae Bin L, Hyeong Joon K, Soo Gil K, Cheol Seong H, Seong-Hyeon H, Young Hwa S, Neung Hun L: Deposition of ZnO thin films by magnetron sputtering for a film bulk acoustic resonator. Thin Solid Films 2003, 435: 179–185. 10.1016/S0040-6090(03)00347-XXionga DP, Tanga XG, Zhaoa WR, Liua QX, Wanga YH, Zhoub SL: Deposition of ZnO and MgZnO films by magnetron sputtering. Vacuum 2013, 89: 254–256.Reyes Tolosa MD, Orozco-Messana J, Lima ANC, Camaratta R, Pascual M, Hernandez-Fenollosa MA: Electrochemical deposition mechanism for ZnO nanorods: diffusion coefficient and growth models. J Electrochem Soc 2011, 158(11):E107-E110.Ming F, Ji Z: Mechanism of the electrodeposition of ZnO nanosheets below room temperature. J Electrochem Soc 2010, 157(8):D450-D453. 10.1149/1.3447738Pullini D, Pruna A, Zanin S, Busquets Mataix D: High-efficiency electrodeposition of large scale ZnO nanorod arrays for thin transparent electrodes. J Electrochem Soc 2012, 159: E45-E51. 10.1149/2.093202jesPruna A, Pullini D, Busquets Mataix D: Influence of deposition potential on structure of ZnO nanowires synthesized in track-etched membranes. J Electrochem Soc 2012, 159: E92-E98. 10.1149/2.003205jesMarotti RE, Giorgi P, Machado G, Dalchiele EA: Crystallite size dependence of band gap energy for electrodeposited ZnO grown at different temperatures. Solar Energy Materials and Solar Cells 2009, 90(15):2356–2361.Yeong Hwan K, Myung Sub K, Jae Su Y: Structural and optical properties of ZnO nanorods by electrochemical growth using multi-walled carbon nanotube-composed seed layers. Nanoscale Res Lett 2012, 7: 13. 10.1186/1556-276X-7-13Elias J, Tena-Zaera R, Lévy-Clément C: Electrodeposition of ZnO nanowires with controlled dimensions for photovoltaic applications: role of buffer layer. Thin Solid Films 2007, 515(24):8553–8557. 10.1016/j.tsf.2007.04.027Zhai Y, Zhai S, Chen G, Zhang K, Yue Q, Wang L, Liu J, Jia J: Effects of morphology of nanostructured ZnO on direct electrochemistry and biosensing properties of glucose oxidase. J Electroanal Chem 2011, 656: 198–205. 10.1016/j.jelechem.2010.11.020Reyes Tolosa MD, Orozco-Messana J, Damonte LC, Hernandez-Fenollosa MA: ZnO nanoestructured layers processing with morphology control by pulsed electrodeposition. J Electrochem Soc 2011, 158(7):D452-D455. 10.1149/1.3593004Gouxa A, Pauporté T, Chivot J, Lincot D: Temperature effects on ZnO electrodeposition. Electrochim Acta 2005, 50(11):2239–2248. 10.1016/j.electacta.2004.10.007Kwok WM, Djurisic , Aleksandra B, Leung , Yu H, Li D, Tam KH, Phillips DL, Chan WK: Influence of annealing on stimulated emission in ZnO nanorods. Appl Phys Lett 2006, 89(18):183112. 183112–3 183112–3 10.1063/1.2378560Donderis V, Hernández-Fenollosa MA, Damonte LC, Marí B, Cembrero J: Enhancement of surface morphology and optical properties of nanocolumnar ZnO films. Superlattices and Microstructures 2007, 42: 461–467. 10.1016/j.spmi.2007.04.068Ghayour H, Rezaie HR, Mirdamadi S, Nourbakhsh AA: The effect of seed layer thickness on alignment and morphology of ZnO nanorods. Vacuum 2011, 86: 101–105. 10.1016/j.vacuum.2011.04.025Michael B, Mohammad Bagher R, Sayyed-Hossein K, Wojtek W, Kourosh K-z: Aqueous synthesis of interconnected ZnO nanowires using spray pyrolysis deposited seed layers. Mater Lett 2010, 64: 291–294. 10.1016/j.matlet.2009.10.065Jang Bo S, Hyuk C, Sung-O K: Rapid hydrothermal synthesis of zinc oxide nanowires by annealing methods on seed layers. J Nanomater 2011, 2011: 6.Peiro AM, Punniamoorthy R, Kuveshni G, Boyle DS, Paul O’B, Donal DC, Bradley , Jenny N, Durrant JR: Hybrid polymer/metal oxide solar cells based on ZnO columnar structures. J Mater Chem 2006, 16(21):2088–2096. 10.1039/b602084dVallet-Regí M, Salinas AJ, Arcos D: From the bioactive glasses to the star gels. J Mater Sci Mater Med 2006, 17: 1011–1017.Peulon S, Lincot D: Mechanistic study of cathodic electrodeposition of zinc oxide and zinc hydroxychloride films from oxygenated aqueous zinc chloride solutions. J Electrochem Soc 1998, 145: 864. 10.1149/1.1838359Dalchiele EA, Giorgi P, Marotti RE, Martín F, Ramos-Barrado JR, Ayouci R, Leinen D: Electrodeposition of ZnO thin films on n-Si(100). Sol. Energy Mater. Sol. Cells 2001, 70: 245. 10.1016/S0927-0248(01)00065-4Courtney IA, Dahn JR: Electrochemical and in situ X‐ray diffraction studies of the reaction of lithium with tin oxide composites. J Electrochem Soc 1997, 144(6):2045–2052. 10.1149/1.183774

Etude des réactions rédox aux interfaces de composés oxygénés présents dans l'environnement

Communication orale

Couches minces : Synthèse et Réactivité. Des outils pour l'étude des processus rédox aux interfaces de composés oxygénés présents dans l'environnement

Communication oral

Processus rédox aux interfaces de composés oxygénés présents dans l'environnement : Pourquoi les composés du manganèse ?

Communication oral

Etude des processus redox aux interfaces de composés oxygénés présents dans l'environnement : Formation des matériaux de référence en couches minces

Communication oral

Caractérisation par absorption UV-Visible de couches minces de composés de fer électrodéposés sur un semi-conducteur transparent, le SnO2

Communication oral

Valorisation of original nanostructured lead oxides thin films issued from an innovating electrochemical depollution process: Application to the total electro-mineralisation of glyphosate

International audienceGlyphosate is a very problematic pollutant in the world. This study presents a simple treatment to degrade it until total mineralisation with no production of AMPA (aminomethylphosphonic acid), its main by-product more toxic and persistent, by using original nanostructured lead oxides thin films. The synthesis conditions of these materials were determined previously in relation to an innovating electrochemical depollution process of water polluted by soluble lead. Different parameters were evaluated such as pH, initial concentration, lead oxide type and consequently its particular morphology. The solutions were systematically analysed by ion chromatography to determine the concentrations of organic pollutants and ionic species produced, and by UV–visible spectroscopy to quantify released lead during process. The thin films were characterized by XRD, SEM and EDS, before and after interaction. The Pb-04 sample type (pure β-PbO$_2$ with cubic needles nanostructures) seems particularly efficient to obtain a total mineralisation with a mineralisation capacity equal to (1127 ± 56) mg of glyphosate/g of material. Moreover, lead was not released in solution due to a total regeneration with the similar crystalline structure. These results are very promising for potential valorisation of heavy metals wastes for future applications at room temperature and very low electrical inputs