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Leone Spiccia - One of the best experts on this subject based on the ideXlab platform.
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aqueous dye sensitized solar cell electrolytes based on the ferricyanide Ferrocyanide redox couple
Advanced Materials, 2012Co-Authors: Torben Daeneke, Yu Uemura, Noel W Duffy, Attila J Mozer, Nagatoshi Koumura, Udo Bach, Leone SpicciaAbstract:: Solar energy conversion efficiencies of over 4% have been achieved in DSCs constructed with aqueous electrolytes based on the ferricyanide-Ferrocyanide redox couple, thereby avoiding the use of expensive, flammable and toxic solvents. This paradigm shift was made possible by the use of a hydrophobic organic carbazole dye.
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the encapsulation of Ferrocyanide by copper ii complexes of tripodal tetradentate ligands novel h bonding networks incorporating heptanuclear and pentanuclear heterometallic assemblies
Inorganic Chemistry, 2001Co-Authors: Richard J Parker, Leone Spiccia, Stuart Robert Batten, John D Cashion, Gary D FallonAbstract:Substitution of the weakly binding aqua ligand in [Cu(tren)OH2]2+ and [Cu(tpa)OH2]2+ (tren = tris(2-aminoethyl)amine; tpa = tris(2-pyridylmethyl)amine) by a cyano ligand on ferricyanide results in the assembly of heteropolynuclear cations around the cyanometalate core. In water, the reduction of the FeIII core to FeII generates complexes that feature heteropolycations in which Ferrocyanide is encapsulated by the CuII moieties: [{Cu(tpa)CN}6Fe][ClO4]8·3H2O 1, [{Cu(tren)CN}6Fe][ClO4]8·10H2O 2, [{Cu(tren)CN}6Fe][Fe(CN)6]2[ClO4]2·15.8H2O 3, and [{Cu(tren)CN}6Fe][{Cu(tren)CN}4Fe(CN)2][Fe(CN)6]4·6DMSO·21H2O 4. The formation of discrete molecules, in preference to extended networks or polymeric structures, has been encouraged through the use of branched tetradentate ligands in conjunction with copper(II), a metal center with the propensity to form five-coordinate complexes. Complex 3 crystallizes in the monoclinic space group P21/c (#14) with a = 14.8674(10), b = 25.9587(10), c = 27.5617(10) A, β = 100.8300(10)...
Yasuhiro Tachibana - One of the best experts on this subject based on the ideXlab platform.
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semiconductor quantum dot sensitized solar cells based on ferricyanide Ferrocyanide redox electrolyte reaching an open circuit photovoltage of 0 8 v
ACS Applied Materials & Interfaces, 2016Co-Authors: Rosemarie M Evangelista, Satoshi Makuta, Shota Yonezu, John Andrews, Yasuhiro TachibanaAbstract:Semiconductor quantum dot sensitized solar cells (QDSSCs) have rapidly been developed, and their efficiency has recently exceeded 9%. Their performances have mainly been achieved by focusing on improving short circuit photocurrent employing polysulfide electrolytes. However, the increase of open circuit photovoltage (VOC) cannot be expected with QDSSCs based on the polysulfide electrolytes owing to their relatively negative redox potential (around −0.65 V vs Ag/AgCl). Here, we demonstrate enhancement of the open circuit voltage by employing an alternative electrolyte, ferricyanide/Ferrocyanide redox couple. The solar cell performance was optimized by investigating the influence of ferricyanide and Ferrocyanide concentration on their interfacial charge transfer and transport kinetics. The optimized ferricyanide/Ferrocyanide species concentrations (0.01/0.2 M) result in solar energy conversion efficiency of 2% with VOC of 0.8 V. Since the potential difference between the TiO2 conduction band edge at pH 7 an...
V I Sergienko - One of the best experts on this subject based on the ideXlab platform.
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colloid stable sorbents for cesium removal preparation and application of latex particles functionalized with transition metals Ferrocyanides
Journal of Hazardous Materials, 2011Co-Authors: V A Avramenko, Svetlana Bratskaya, V V Zheleznov, I V Sheveleva, O V Voitenko, V I SergienkoAbstract:Abstract In this paper we suggest a principally new approach to preparation of colloid stable selective sorbents for cesium uptake using immobilization of transition metals (cobalt, nickel, and copper) Ferrocyanides in nanosized carboxylic latex emulsions. The effects of Ferrocyanide composition, pH, and media salinity on the sorption properties of the colloid stable sorbents toward cesium ions were studied in solutions containing up to 200 g/L of sodium nitrate or potassium chloride. The sorption capacities of the colloid sorbents based on mixed potassium/transition metals Ferrocyanides were in the range 1.3–1.5 mol Cs/mol Ferrocyanide with the highest value found for the copper Ferrocyanide. It was shown that the obtained colloid-stable sorbents were capable to penetrate through bulk materials without filtration that made them applicable for decontamination of solids, e.g. soils, zeolites, spent ion-exchange resins contaminated with cesium radionuclides. After decontamination of liquid or solid radioactive wastes the colloid-stable sorbents can be easily separated from solutions by precipitation with cationic flocculants providing localization of radionuclides in a small volume of the precipitates formed.
G.f. Schiefelbein - One of the best experts on this subject based on the ideXlab platform.
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Ferrocyanide Safety Project Task 3 Ferrocyanide Aging Studies FY 1993 annual report
1993Co-Authors: Lilga, M.r. Lumetta, G.f. SchiefelbeinAbstract:The Hanford Ferrocyanide Task Team is addressing issues involving Ferrocyanide precipitates in single-shell waste storage tanks (SSTs), in particular the storage of waste in a safe manner. This Task Team, composed of researchers from Westinghouse Hanford Company (WHC), Pacific Northwest Laboratory (PNL), and outside consultants, was formed in response to the need for an updated analysis of safety questions about the Hanford Ferrocyanide tanks. The Ferrocyanides Safety Project at PNL is part of the Waste Tank Safety Program led by WHC. The overall purpose of the WHC program, sponsored by the US Department of Energy`s Tank Farm Project Office, is to (1) maintain the Ferrocyanide tanks with minimal risk of an accident, (2) select one or more strategies to assure safe storage, and (3) close out the unreviewed safety question (USQ). This annual report gives the results of the work conducted by PNL in FY 1993 on Task 3, Ferrocyanides Aging Studies, which deals with the aging behavior of simulated Ferrocyanide wastes. Aging processes include the dissolution and hydrolysis of nickel Ferrocyanides in high pH aqueous solutions. Investigated were the effects of pH variation; ionic strength and sodium ion concentration; the presence of anions such as phosphate, carbonate, and nitrate;more » temperature; and gamma radiation on solubility of Ferrocyanide materials including In-Farm-lA, Rev. 4 flowsheet-prepared Na{sub 2}NiFe(CN){sub 6}.« less
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FY 1993 Ferrocyanide Tank Safety Project: Effects of Aging on Ferrocyanide Wastes test plan for the remainder of FY 1993
1993Co-Authors: Lilga, G.f. SchiefelbeinAbstract:Researchers in the Hanford Ferrocyanide Task Team are studying safety issues associated with Ferrocyanide precipitates in single shell waste storage tanks (SST). Ferrocyanide is a stable complex of ferrous, ion and cyanide ion that is considered nontoxic because it does not dissociate readily in aqueous solutions. However, in the laboratory at temperatures in excess of 180{degrees}C and in the presence of oxidizers such as nitrates and nitrites, dry Ferrocyanide and Ferrocyanide waste stimulants can be made to react exothermically. The Ferrocyanide Safety Project at the Pacific Northwest Laboratory (PNL) is part of the Waste Tank Safety Program at Westinghouse Hanford Company (WHC). The purpose of the WHC program is to (1) maintain the Ferrocyanide tanks with minimal risk of an accident, (2) select one or more strategies to assure safe storage, and (3) close out the unreviewed safety question (USQ). Tank Ferrocyanide wastes were exposed to highly alkaline wastes from subsequent processing operations. Chemical reactions with caustic may have changed the Ferrocyanide materials during 40 years of storage in the SSTs. Research in the {open_quotes}Effects of Aging on Ferrocyanide Wastes{close_quotes} task is targeted at studying aging of Ferrocyanide tank simulants and other Ferrocyanide materials to obtain a better understanding ofmore » how tank materials may have changed over the years. The research objective in this project is to determine the solubility and hydrolysis characteristics of simulated Ferrocyanide tank wastes in alkaline media. The behavior of Ferrocyanide simulant wastes is being determined by performing chemical reactions under conditions that might mimic the potential ranges in SST environments. Experiments are conducted at high pH, at high ionic strength, and in the presence of gamma radiation. Verification of simulant study findings by comparison with results with actual waste will also be required.« less
S.a. Bryan - One of the best experts on this subject based on the ideXlab platform.
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Ferrocyanide tank safety program: Cesium uptake capacity of simulated Ferrocyanide tank waste. Final report
1995Co-Authors: I.e. Burgeson, S.a. BryanAbstract:The objective of this project is to determine the capacity for {sup 137}Cs uptake by mixed metal Ferrocyanides present in Hanford Site waste tanks, and to assess the potential for aggregation of these {sup 137}Cs-exchanged materials to form ``hot-spots`` in the tanks. This research, performed at Pacific Northwest Laboratory (PNL) for Westinghouse Hanford Company, stems from concerns regarding possible localized radiolytic heating within the tanks. After Ferrocyanide was added to 18 high-level waste tanks in the 1950s, some of the Ferrocyanide tanks received considerable quantities of saltcake waste that was rich in {sup 137}Cs. If radioactive cesium was exchanged and concentrated by the nickel Ferrocyanide present in the tanks, the associated heating could cause tank temperatures to rise above the safety limits specified for the Ferrocyanide-containing tanks, especially if the supernate in the tanks is pumped out and the waste becomes drier.
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Cesium uptake capacity of simulated Ferrocyanide tank waste. Interim report FY 1994, Ferrocyanide Safety Project
1994Co-Authors: I.e. Burgeson, S.a. Bryan, L.e. BurgerAbstract:The objective of this project is to determine the capacity for {sup 137}CS uptake by mixed metal Ferrocyanides present in Hanford waste tanks, and to assess the potential for aggregation of these {sup 137}CS exchanged materials to form tank ``hot-spots.`` This research, performed at the Pacific Northwest Laboratory (PNL) for the Westinghouse Hanford Company (WHC), stems from concerns of possible localized radiolytic heating within the tanks. If radioactive cesium is exchanged and concentrated by the remaining nickel Ferrocyanide present in the tanks, this heating could cause temperatures to rise above the safety limits specified for the Ferrocyanide tanks. For the purposes of this study, two simulants, In-Farm-2 and U-Plant-2, were chosen to represent the wastes generated by the scavenging processes. These simulants were formulated using protocols from the original cesium scavenging campaign. Later additions of cesium-rich wastes from various processes also were considered. The simulants were prepared and centrifuged to obtain a moist Ferrocyanide sludge. The centrifuged sludges were treated with the original supernate spiked with a known amount of cesium nitrate. After analysis by flame atomic absorption spectrometry, distribution coefficients (K{sub d}) were calculated. The capacity of solid waste simulants to exchange radioactive cesium from solution was examined. Initial more » results showed that the greater the molar ratio of cesium to cesium nickel Ferrocyanide, the less effective the exchange of cesium from solution. The theoretical capacity of 2 mol cesium per mol of nickel Ferrocyanide was not observed. The maximum capacity under experimental conditions was 0.35 mol cesium per mol nickel Ferrocyanide. Future work on this project will examine the layering tendency of the cesium nickel Ferrocyanide species. « less