Abstract:The copper cystamine complex is a suitabIe system for the homogeneous catalysis of oxygen cathodic reduction in aqueous solutions. A steady state cathodic current density of 3.2 mAlcm2 at 0.2V and an overvoltage decrease of 400mV was observed in oxygen-saturated solutions of equimolar concentrations of CuII ions and cystamine (5 x mol dm-3) at pH 4.5. For a given value of C1-ion concentration and pH the catalytic current can be expressed by :The optical, magnetic and kinetic properties of the catalyst were inv… Show more
“…The valence state of copper in these chrsters is usually assumed to be Cu(f). However, there are indications that Cu(II) clusters also are abIe to bind dixygen and promote electron transfer horn the hgands towards the dioxygen [33,34].…”
Instead, a reaction model is proposed, which is based upon the involvement of I thiyl-and a superoxoactivati Cu(II) complex, respectively. These two types of complexes are operative in a chainlike propagation cycle _
“…The valence state of copper in these chrsters is usually assumed to be Cu(f). However, there are indications that Cu(II) clusters also are abIe to bind dixygen and promote electron transfer horn the hgands towards the dioxygen [33,34].…”
Instead, a reaction model is proposed, which is based upon the involvement of I thiyl-and a superoxoactivati Cu(II) complex, respectively. These two types of complexes are operative in a chainlike propagation cycle _
“…Usually these electrodes are coated with catalytic layers (1)(2)(3) or are immersed in catalytic suspensions (4,5) to overcome their great deviation from thermodynamic reversibility. The homogeneous catalysis of the oxygen electrode is treated in previous studies (6,7).…”
Section: Atomic Energy Commission Nuclear Research Centre-negev Beer-...mentioning
confidence: 99%
“…Two types of electrodes (1.0 • 2.8 cm each) were prepared (1): the noncatalytic electrode (type A) was a Ni gauze on which carbon was deposited, and the catalytic one (type B) was a similar electrode but impregnated with Fe(III)-PhC. The instrumentation is described elsewhere (6,8).…”
Section: Atomic Energy Commission Nuclear Research Centre-negev Beer-...mentioning
“…7,[12][13][14][15] Although studies on heterogeneous catalysts (catalyst immobilized on the electrode) are numerous in the literature and most of them are in aqueous solution, [16][17][18] homogenous catalysts (catalyst in solution) for ORR in aprotic media are rare. [19][20][21][22][23] For example, Mho S. and coworkers reported the interaction of reduced cobaltphthalocyanine with oxygen and proposed that the catalytic activities of phthalocyanines are achieved through a conventional regenerative catalytic mechanism. 24 Nyokong and her coworkers also studied the homogeneous catalytic activities of various metalloporphyrin (MPP) complexes in aqueous solution.…”
Electrochemical and in situ spectroelectrochemical behaviors and electrocatalytic reduction of molecular oxygen with titanyl phthalocyanines (TiPc) bearing 3,4-(methylenedioxy)-phenoxy substituents were performed in aprotic solvents. Multi electrons and metal-based and ring-based redox processes of TiPcs indicate their possible electrocatalytic activity toward many target species. Different numbers and positions of the substituents of the complexes affect the peaks' character and assignment of the processes. The presence of O2 in the electrolyte system influences the electrochemical and spectral responses of TiPcs. Electrochemical and in situ spectroelectrochemical analysis indicates interaction of molecular oxygen with TiPcs and these interaction mechanisms depend on both the substituent environments of the complexes and the electrolyte system. Langmuir-Blodgett films of the complexes also catalyze molecular oxygen in aqueous media, which is a desired property for their practical application.
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