The Experts below are selected from a list of 30 Experts worldwide ranked by ideXlab platform
Liu Chun - One of the best experts on this subject based on the ideXlab platform.
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Synthesis, Characterization and Electrochemical Behavior of Iron Substituted Tungstosilicates Positional Isomer
Chinese Journal of Inorganic Chemistry, 2020Co-Authors: Ma Rong, Liu ChunAbstract:： The four heteropoly isomers K3H2[α-,β i-SiW11Fe(H2O)O39]· xH2O(β i=β 1,β 2,β 3)were prepared and Characterized by elementary analysis, IR and UV Spectroscopy. Its electrochemical behavior in aqueous solution has been discussed. The order of Polarographic Half-Wave Potential E1/2 of heteropoly anions is as follows:β 2 β 1 β 3 α . Its reduction process involves an one-electron reduction of Fe? and a pair of two-electron reduction of W? . Epolidation of maleic acid with H2O2 Catalyzed by heteropoly positional isomers was studied.β 3 isomers are the most active.
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Synthesis, Characterization and Catalytic Activity of Positional Isomers of Titanium Substituted Tungstosilicates
Chinese Journal of Applied Chemistry, 2020Co-Authors: Ma Ling, Liu ChunAbstract:Four heteropoly isomers α-K 6\[SiW 11TiO 40\]·xH 2O and β i-K 6\[SiW 11TiO 40\]·xH 2O(β i=β 1,β 2,β 3) were synthesized and characterized by elemental analysis, IR, UV spectrometry, polarography, cyclic voltammetry and 183W NMR. The 183W NMR results suggested that tungsten atoms are in six chemical enviroments for α,β 1,β 3 -isomers and in nine chemical enviroments for β 2-isomer, indicating compounds formed are all mono-substituted heteropoly complexes of Keggin structure. The order of Polarographic Half-Wave Potential E 1/2 of the heteropoly anions was as follows:β 2β 1β 3α. Their reduction processes involved an one-electron reduction of Ti(Ⅳ) and a pair of two-electron reduction of W(Ⅵ). The synthesized isomers showed better catalytic activity in epoxidation of maleic acid with H 2O 2 and the β-isomer was higher than α-isomer in catalytic activity .
David N. Hume - One of the best experts on this subject based on the ideXlab platform.
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Effect of ionic strength on the Polarographic Half-Wave Potential
Analytica Chimica Acta, 1991Co-Authors: Richard A. Durst, David N. HumeAbstract:Abstract The shift in the Polarographic Half-Wave Potential caused by changes in the concentration of a non-complexing supporting electrolyte was investigated. The depolarizer systems studied were the cadmium(II) and zinc(II) amine complex ions, and the cadmium(II), zinc(II), indium(III) and thallium(I) aquo ions. These systems exhibited Half-Wave Potential shifts that were dependent on five factors affected by the ionic strength of the solution: the activity and diffusion coefficients of the depolarizer ions, the activity of the complexing agent and/or water and the liquid junction Potential. An equation was derived relating these factors to the Half-Wave Potential shift and evaluated for the change in the activity coefficient of the depolarizer over the ionic strength range 4–10. As expected, the observed Potential shift showed a strong correlation with the charge and primary hydration numbers of the aquo ions.
Richard A. Durst - One of the best experts on this subject based on the ideXlab platform.
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Effect of ionic strength on the Polarographic Half-Wave Potential
Analytica Chimica Acta, 1991Co-Authors: Richard A. Durst, David N. HumeAbstract:Abstract The shift in the Polarographic Half-Wave Potential caused by changes in the concentration of a non-complexing supporting electrolyte was investigated. The depolarizer systems studied were the cadmium(II) and zinc(II) amine complex ions, and the cadmium(II), zinc(II), indium(III) and thallium(I) aquo ions. These systems exhibited Half-Wave Potential shifts that were dependent on five factors affected by the ionic strength of the solution: the activity and diffusion coefficients of the depolarizer ions, the activity of the complexing agent and/or water and the liquid junction Potential. An equation was derived relating these factors to the Half-Wave Potential shift and evaluated for the change in the activity coefficient of the depolarizer over the ionic strength range 4–10. As expected, the observed Potential shift showed a strong correlation with the charge and primary hydration numbers of the aquo ions.
Ma Rong - One of the best experts on this subject based on the ideXlab platform.
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Electrochemical Properties and Catalytic Activity of Undecatungstomaganosilicate Isomers
Chinese Journal of Applied Chemistry, 2020Co-Authors: Ma Rong, Lui Chun, Wang ShouAbstract:Synthetic method and electrochemical properties of undecatungstomanganosilicate isomers α and β i K n H 6- n [SiW 11 Mn(H 2O)O 39 ]· x H 2O( β i = β 1, β 2, β 3) are reported. The effect of structure on the redox has been investigated. The order of Polarographic half wave Potential E 1/2 of heteropoly anions as follows: β 2 β 1 β 3 α in epoxidation of maleic acid with H 2O 2 is β 3(87 86%) β 1(82 50%) α (64 20%) β 2(56 10%).
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Synthesis, Characterization and Electrochemical Behavior of Iron Substituted Tungstosilicates Positional Isomer
Chinese Journal of Inorganic Chemistry, 2020Co-Authors: Ma Rong, Liu ChunAbstract:： The four heteropoly isomers K3H2[α-,β i-SiW11Fe(H2O)O39]· xH2O(β i=β 1,β 2,β 3)were prepared and Characterized by elementary analysis, IR and UV Spectroscopy. Its electrochemical behavior in aqueous solution has been discussed. The order of Polarographic Half-Wave Potential E1/2 of heteropoly anions is as follows:β 2 β 1 β 3 α . Its reduction process involves an one-electron reduction of Fe? and a pair of two-electron reduction of W? . Epolidation of maleic acid with H2O2 Catalyzed by heteropoly positional isomers was studied.β 3 isomers are the most active.
Galina A. Tsirlina - One of the best experts on this subject based on the ideXlab platform.
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Half-Wave Potential as affected by supporting electrolyte nature: Interplay of adsorption and ionic association for electroreduction of V(V)-mixed addenda Keggin tungstophosphate
Electrochimica Acta, 2013Co-Authors: Leonid V. Pugolovkin, Maria A. Naumova, A. A. Fedorova, M. I. Borzenko, Galina A. TsirlinaAbstract:Abstract V(V)-mixed addenda Keggin tungstophosphate demonstrates the pronounced dependence of Polarographic Half-Wave Potential E1/2 at positively charged mercury surface on the nature of supporting alkali metal cation. This effect (typical for polyoxometalates) complicates the straightforward application of E1/2 values to analysis of various thermodynamic trends and correlations. Cation-induced E1/2 shifts are explained under assumption of Keggin anions reduction from compact adlayers containing the cations. Strong adsorption of the reactant is confirmed by a decrease of interfacial surface tension and by pronounced inhibitory effect on the outer-sphere electron transfer reactions. Stabilization of adlayers by co-adsorbing supporting cations increases in a series Li+