14362-44-8Relevant articles and documents
Yost, D. M.,Zabaro, S.
, p. 1181 - 1181 (1926)
Sustained and Damped pH Oscillation in the Periodate-Thiosulfate Reaction in a Continuous-Flow Stirred Tank Reactor
Rabai, Gyula,Beck, Mihaly T.,Kustin, Kenneth,Epstein, Irving R.
, p. 2853 - 2858 (1989)
The reaction between IO4- and S2O32- exhibits a variable stoichiometry in acetate buffer.With a large excess of IO4-, the products are IO3- and SO42-.In excess thiosulfate, IO4- is reduced
Popoff, S.,Whitman, J. L.
, p. 2259 - 2275 (1925)
Sarkar, P. B.,Ghosh, N. N.
, p. 209 - 212 (1956)
Skrabal, A.,Gruber, J.
, (1916)
STUDIES ON THE μ-(NN')-ETHYLENEDIAMINETETRA-ACETATO-DI-μ-OXO-BIS-, 2-, COMPLEX IN AQUEOUS SOLUTIONS. FORMATION OF AN AQUO-ION AND REDOX PROPERTIES
Soares, Allan B.,Taylor, Craig R.,Sykes, Geoffrey A.
, p. 1101 - 1104 (1980)
The aquation of 2- (edta=ethylenediaminetetra-acetate) to W2O42+ (or a closely related species) proceeds to completion in HCl>=2 mol dm3-.First-order kinetics have been observed, with the rate constant (1.16*10-4 s-1 at 25 deg C) in 2 mol dm-3 HCl some 60 times less than for the corresponding reaction of 2-.With HClO4>=2 mol dm-3 aquation is accompained by oxidation to WVI.No aquation (or oxidation) has been observed with HClO4-3, under which condition redox reactions of the edta complex could be investigated.At 25 deg C, I=0.50 mol dm-3 (H-LiClO4) rate constants for the first stage of the 1:2 oxidations of 2- with 2- and 3+ (phen=1,10-phenantroline) are 6.3*105 dm3 mol-1 s-1 and >107 dm3 mol-1 s-1 respectively.For the 2- reaction activation parameters are ΔH+=5.4 kcal mol-1 s-1 and ΔS+=-13.8 cal K-1 mol-1 respectively.Rate constants (dm3 mol-1 s-1) for other oxidants, I=0.10 mol dm-3, are 3- (0.058), 3+ (2.0) (bipy=2,2'-bipyridine), and I3- (ca. 20).The complex 2- is a much stronger reducing agent than 2-.
Datta, A. K.
, p. 404 - 404 (1932)
Kinetics and Mechanisms of the Oxidation of Hydrazine by Aqueous Iodine
Liu, Rong Ming,Margerum, Dale W.
, p. 2531 - 2537 (1998)
Kinetics for the reactions of I2 with excess N2H5+/N2H4 and I- are measured by the loss of I3- over a wide range of acidity from pH 0.35 to 8.0 at 25.0 °C, μ = 0.50 M. Pseudo-first-order rate constants increase by factors of more than 107 with increase of pH, hydrazine, and buffer concentrations. Below pH 1, I2 reacts directly with N2H5+ which has a relative reactivity that is 2.4 × 107 times smaller than N2H4 (the dominant reactant at pH ≥ 1). Kinetic evidence for IN2H4+ as a steady-state species is found below pH 3. From pH 3.5 to 6.3, rate constants are measured by stopped-flow methods and at higher pH by pulsed-accelerated-flow methods. A multistep mechanism is proposed where I2 reacts rapidly with N2H4 to form an I2N2H4 adduct (KA = 2.0 × 104 M-1) that is present in appreciable concentrations above pH 6. The adduct undergoes general base-assisted deprotonation accompanied by loss of I- in the rate-determining step. Subsequent intermediates react rapidly with another I2 to form N2 as a final product. At high pH, hydrazine acts as a general base as well as the initial nucleophile. Rate constants for various bases (H2O, CH3COO-, HPO42-, N2H4, and OH-) fit a Br?nsted β value of 0.46. Values for the second-order rate constants (M-1 s-1) for I2N2H4 reactions with CH3COO-, HPO42-, N2H4 and OH- are 7.5 × 103, 2.0 × 105, 8.5 × 105, and 4.8 × 108, respectively.
In situ growth of mirror-like platinum as highly-efficient counter electrode with light harvesting function for dye-sensitized solar cells
Zhang, Nan Nan,Zhang, Bo,Li, Yu Hang,Hou, Yu,Yang, Shuang,Zhong, Ju Hua,Yang, Hua Gui
, p. 1641 - 1646 (2014)
In this work, we prepared a continuous nanostructured Pt-mirror film with metallic lustre and good adhesion to the F-doped tin oxide conducting glass (FTO) substrate through a simple in situ growth method, which retains a good catalytic activity and more importantly, exhibits significant light reflection for light-harvesting. The dye-sensitized solar cells (DSCs) fabricated with Pt-M CE exhibited superior photovoltaic performance compared with the conventional Pt CE. The enhancements of the short-circuit current density and energy conversion efficiency are 15.3% and 18.5%, respectively. Such significant enhancement of the short-circuit current density was found to be related to the excellent light reflection and high catalytic activity of the Pt-M CE. This has been proved by ultraviolet and visible reflection spectra (UV/Vis), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV).
Electron transfer. 144. Reductions with germanium(II)
Babich, Olga A.,Gould, Edwin S.
, p. 4119 - 4122 (2000)
Solutions 0.2-0.4 M in Ge(II) and 6 M in HCl, generated by reaction of Ge(IV) with H3PO2, are stable for more than 3 weeks and can be diluted 200-fold with dilute HCl to give GeCl3- preparations to be used in redox studies. Kinetic profiles for the reduction of Fe(III) by Ge(II), as catalyzed by Cu(II), implicate the odd-electron intermediate, Ge(III), which is formed from Cu(II) and Ge(II) (k = 30 M-1 s-1 in 0.5 M HCl at 24 °C) and which is consumed by reaction with Fe(III) (k = 6 x 102 M-1 s-1). A slower direct reaction between Ge(II) and Fe(III) (k = 0.66 M-1 s-1) can be detected in 1.0 M HCl. The reaction of Ge(II) with I3- in 0.01-0.50 M iodide is zero order in oxidant and appears to proceed via a rate-determining heterolysis of a Ge(II)-OH2 species (k = 0.045 s-1) which is subject to H+-catalysis. Reductions of IrCl62- and PtCl62- by Ge(II) are strongly Cl--catalyzed. The Ir(IV) reaction proceeds through a pair of 1e- changes, of which the initial conversion to Ge(III) is rate-determining, whereas the Pt(IV) oxidant probably utilizes (at least in part) an inner-sphere Pt(IV)-Cl-Ge(II) bridge in which chlorine is transferred (as Cl+) from oxidant to reductant. The 2e- reagent, Ge(II), like its 5s2 counterpart, In(I), can partake in 1e- transactions, but requires more severe constraints: the coreagent must be more powerfully oxidizing and the reaction medium more halide-rich.
Skrabal, A.
, (1911)
Complex kinetics of a landolt-type reaction: The later phase of the thiosulfate-iodate reaction
Horvath, Attila K.,Varga, Denes,Nagypal, Istvan
, p. 5752 - 5758 (2010)
The thiosulfate-iodate reaction has been studied spectrophotometrically in slightly acidic medium at 25.0 ± 0.1 °C in acetate/acetic acid buffer by monitoring the absorbance at 468 nm at the isosbestic point of iodine-triiodide ion system. The formation of iodine after the Landolt time follows a rather complex kinetic behavior depending on the pH and on the concentration of the reactants as well. It is shown that the key intermediate of the reaction is I2O2, its equilibrium formation from the well-known Dushman reaction along with their further reactions followed by subsequent reactions of HOI, HIO2, S2O3OH -, and S2O3I- adequately accounts for all the experimentally measured characteristics of the kinetic curves. A 19-step kinetic model is proposed and discussed with 13 fitted and 7 fixed parameters in detail.
The Oscillatory Landolt Reaction. Empirical Rate Law Model and Detailed Mechanism.
Gaspar, Vilmos,Showalter, Kenneth
, p. 4869 - 4876 (1987)
The iodate oxidation of sulfite and ferrocyanide when carried out in a continuous flow stirred tank reactor exhibits large-amplitude oscillations in pH accompanied by an almost constant concentration of iodide.A description of the reaction in terms of component processes and associated empirical rate laws is used to model the dynamical behavior.Limitations and potential refinements of the empirical rate law model are discussed.A detailed mechanism consistent with the component process description is presented.
Kinetics and Mechanism of the Autoinhibitory Iodide-Thiocyanate Reaction
Simoyi, Reuben H.,Epstein, Irving R.,Kustin, Kenneth
, p. 2792 - 2795 (1989)
The kinetics and mechanism of the reaction between iodine and thiocyanate have been investigated in the pH range 1-9.Two limiting stoichiometries are found: at pH > 4, 4 I2 + SCN- + 4 H2O -> SO42- + ICN + 7 I- + 8 H+
Cooke
, p. 259 (1979)
Pulse radiolysis study of I- oxidation with radical anions Cl2.- in an aqueous solution
Ershov,Janata,Gordeev
, p. 1378 - 1382 (2005)
Radiation-chemical transformations of chloride solutions in the presence of iodide additives were studied by pulse radiolysis. Radical anion Cl 2.- oxidize I- ion, while in the secondary reactions Cl2 reacts with I- to form a mixed trihalide ion ICl2-. A reaction model that satisfactorily describes the experimental data was proposed.
Topf
, p. 137 - 217 (1887)
Iodide modified electrodes for the electrochemical detection of environmentally hazardous materials
Su, Buo-Wei,Thiagarajan, Soundappan,Chen, Shen-Ming
, p. F157-F164 (2008)
Electrochemical deposition and chemisorption studies of iodide film have been done on the glassy carbon electrode (GCE) and polycrystalline gold electrode (poly GE). The iodide film preparation under different conditions and its stability were examined. Further, the redox activity of the iodide modified film on GCE and poly GE was examined in different pH solutions. Here, the electrochemically deposited iodide film on GCE showed good stability and was electrochemically active at pH 1.5 and 4 solutions, while the chemisorbed iodide film on poly GE was found active and stable at pH 9 and 13 solutions. The iodide modified GCEs exhibits a good electrocatalytic activity for the oxidation of As (III) and the reduction of Cr (VI), respectively. A detailed study for As (III) oxidation has been done by using the rotating ring-disk electrode technique. Meanwhile, chemisorbed iodide film on poly GE shows electrocatalytic reduction reactions of IO 3- by using different techniques like cyclic voltammetry and differential pulse voltammetry. To examine the practical analytical utility of the proposed electrode, the real sample analyses for arsenic and chromate detection have been examined and the results were found satisfactory.
Platinum-free binary Co-Ni alloy counter electrodes for efficient dye-sensitized solar cells
Chen, Xiaoxu,Tang, Qunwei,He, Benlin,Lin, Lin,Yu, Liangmin
, p. 10799 - 10803 (2014)
Dye-sensitized solar cells (DSSCs) have attracted growing interest because of their application in renewable energy technologies in developing modern low-carbon economies. However, the commercial application of DSSCs has been hindered by the high expenses of platinum (Pt) counter electrodes (CEs). Here we use Pt-free binary Co-Ni alloys synthesized by a mild hydrothermal strategy as CE materials in efficient DSSCs. As a result of the rapid charge transfer, good electrical conduction, and reasonable electrocatalysis, the power conversion efficiencies of Co-Ni-based DSSCs are higher than those of Pt-only CEs, and the fabrication expense is markedly reduced. The DSSCs based on a CoNi0.25 alloy CE displays an impressive power conversion efficiency of 8.39 %, fast start-up, multiple start/stop cycling, and good stability under extended irradiation. A mild hydrothermal reduction strategy has been used to generate Pt-free binary Co-Ni alloys for use as counter electrode (CE) materials in dye-sensitized solar cells (DSSCs). These materials offer high electrocatalytic activity toward I3-, good electron conduction, as well as cost-effectiveness. A conversion efficiency of 8.39 % was measured under one sun irradiation, which is much higher than the 6.96 % from platinum-based DSSCs.
A solvent-free strategy to realize the substitution of I- for IO3- in a BiOIO3 photocatalyst with an opposite charge transfer path
Xie, Jing,Cao, Yali,Hu, Jindou,Tang, Yakun,Jia, Dianzeng
, p. 1424 - 1431 (2020)
Substitutional doping is an effective way to improve photocatalytic activity, but substituting an individual ion for an atomic group has always been difficult to achieve. Herein, a simple in situ solvent-free strategy is reported for the synthesis of a photocatalyst by replacing IO3- in BiOIO3 with I- (BiOIO3-P42) via regulating the oxidation-reduction environment, which has been realized by changing the viscosity of the reaction system. Exhilaratingly, the change in the viscosity of the reaction system facilitated the phase composition change from pure BiOIO3 to I--doped BiOIO3 and then to pure BiOIO3, which could be attributed to the synergistic effect of acidity and reducibility for various viscosities. This interesting phenomenon has been identified by XRD, XPS, SEM and HRTEM. Benefiting from the different valence states of iodine in I- and IO3-, the photogenerated electrons and holes could move in opposite directions due to the driving force provided by electrostatic attraction. I--doped BiOIO3 therefore demonstrates an optimal photocatalytic removal rate in the degradation of methyl orange and bisphenol A, which is about two times higher than that of pure BiOIO3. We anticipate that such an in situ substitutional doping technique can be further investigated as a convenient method to design nanomaterials with boosted photocatalytic performance.
Effect of dissolved oxygen on the oxidation of dithionate ion. Extremely unusual kinetic traces
Lente, Gabor,Fabian, Istvan
, p. 4019 - 4025 (2004)
The effect of dissolved oxygen on the acid-dependent disproportionation of dithionate ion (S2O62-) and its oxidation with a number of reagents (I2, Br2, I3-, Br3-, IO3-, BrO3 -, IO4-, MnO4-, Cr(VI), Ce(VI), and H2O2) were studied. Dithionate ion is remarkably inert at room temperature, and heating to elevated temperatures (50-90 °C) was necessary to observe detectable reaction rates in all of these processes. It was confirmed that dithionate ion is never oxidized directly; its redox reactions are zeroth-order with respect to the oxidizing agent and proceed through disproportionation and subsequent fast oxidation of the sulfur(IV) formed. The effect of dissolved oxygen is attributable to its reaction with sulfur(IV) produced in the disproportionation. This autoxidation occurs only with a catalyst. Cerium(III) and iodide ions were shown to catalyze the autoxidation, and their effect on the kinetic traces was studied. In a few cases, highly unusual kinetic traces, such as straight lines with sharp break points, inverted parabolas, and a combination of these, were detected and successfully interpreted in terms of simple kinetic and stoichiometric considerations.
High-Amplitude Hydrogen Ion Concentration Oscillation in the Iodate-Thiosulfate-Sulfite System under Closed Conditions
Rabai, Gy.,Beck, M. T.
, p. 4831 - 4835 (1988)
In the closed system of iodate, hydrogen sulfite, and thiosulfate, high-amplitude, greatly damped pH oscillation occurs in unusually narrow concentration ranges of reactants.A semiquantitative description of the kinetic curves has been made in terms of the empirical rate laws of the subsystems by making allowance for cross effects.The sceleton model is closely related to the Lotka model, the archetype of chemical oscillators.A possible mechanism is suggested to give an account of experimental findings.
ELECTROCHEMICAL STUDY OF 2 AND Fe(NO)2IPPh3 IN DMF AND EVIDENCE FOR THEIR COMPLETE IONIZATION
Piazza, G.,Innorta, G.
, p. 257 - 264 (1982)
2 and Fe(NO)2IPPh3 are completely ionized in DMF; the resulting Fe(NO)+2 and Fe(NO)2PPH+2 can be reduced at a mercury electrode giving rise to the neutral Fe(NO)2 which is known to be a powerful catalyst.
Kinetics and mechanism of the oxidation of tetrathionate by iodine in a slightly acidic medium
Kerek, Attila,Horvath, Attila K.
, p. 4235 - 4241 (2007)
The iodine-tetrathionate reaction has been reinvestigated spectrophotometrically at T = 25.0 ± 0.1°C and at an ionic strength of 0.5 M adjusted by sodium acetate as a buffer component in both the absence and presence of the iodide ion in the pH range of 4.25-5.55. The reaction was found to be independent of pH within the range studied, and it was clearly demonstrated that the reaction proceeds via an intermediate S4O 6I- formed in a pre-equilibrium. Iodide dependence of the kinetic curves strongly suggests that the iodide ion has to be involved in this equilibrium. Further reactions of the intermediate, including its hydrolysis and reaction with iodide, leads to the strict stoichiometry characterized by S 4O62- + 7I2 + 10H2O → 4SO42- + 14I- + 20H+. A seven-step kinetic model with three fitted kinetic parameters is suggested and discussed. A rate equation is also derived from which a sound explanation of the iodide dependence of the apparent rate coefficient is presented. Furthermore, it has also been pointed out that formation of the triiodide ion alone is not sufficient to take the retardation effect of the iodide ion into account quantitatively.
Temperature Dependence of the Equilibrium Constant for Iodine Hydrolysis at Temperatures between 25 and 120 deg C
Burns, William G.,Matsuda, Masami,Sims, Howard E.
, p. 1443 - 1447 (1990)
The equilibrium constant for iodine hydrolysis at elevated temperatures has been investigated using absorption spectroscopy and a simulation computer program.The temperature dependence of the aqueous I2 maximum extinction coefficient for visible light (at 460 nm) was first evaluated in a preliminary experiment using saturated I2 solution.The time dependence of I2 concentrations in dilute solution has subsequently been measured using the temperature-dependent extinction coefficient.The results were analysed by the simulation program, in which 11 normally accepted react ions were considered, and the equilibrium constant, K, was estimated.It was concluded that the K value at temperatures ranging between 25 and 120 deg C may be expressed by logK(T) = 13880/T - 0.2445T + 308.4 log T - 749.1 where the units of K and T are mol2 dm-6 and K, respectively.
A Novel Single-Atom Electrocatalyst Ti1/rGO for Efficient Cathodic Reduction in Hybrid Photovoltaics
Liang, Suxia,Zhu, Chao,Zhang, Naitian,Zhang, Shuo,Qiao, Botao,Liu, Hua,Liu, Xiaoyan,Liu, Zheng,Song, Xuedan,Zhang, Heming,Hao, Ce,Shi, Yantao
, (2020/04/15)
Single-atom catalysts (SACs) are a frontier research topic in the catalysis community. Carbon materials decorated with atomically dispersed Ti are theoretically predicted with many attractive applications. However, such material has not been achieved so far. Herein, a Ti-based SAC, consisting of isolated Ti anchored by oxygen atoms on reduced graphene oxide (rGO) (termed as Ti1/rGO), is successfully synthesized. The structure of Ti1/rGO is characterized by high-angle annular dark-field scanning transmission electron microscopy and X-ray absorption fine structure spectroscopy, being determined to have a five coordinated local structure TiO5. When serving as non-Pt cathode material in dye-sensitized solar cells (DSCs), Ti1/rGO exhibits high electrocatalytic activity toward the tri-iodide reduction reaction. The power conversion efficiency of DSCs based on Ti1/rGO is comparable to that using conventional Pt cathode. The unique structure of TiO5 moieties and the crucial role of atomically dispersed Ti in Ti1/rGO are well understood by experiments and density functional theory calculations. This emerging material shows potential applications in energy conversion and storage devices.
