Reversible solid-state redox reaction

PANI/MnO nanocomposite, synthesized by a facile and effective one-step solid-state redox reaction between frozen aniline and solid KMnO, displayed reversible and highly efficient UV photoresponse properties [182]. Yu et al. [183,184] reported high photoelectrocatalytic activity of... 

A potentiometric electrochemical cell consisting of a reference electrode, solid-state electrolyte(s), and an indicator electrode can provide information about the partial pressure of gas in the same way as the cells utilizing ion-selective electrodes and liquid electrolytes can. The general mechanism is as follows. A sample gas, which is part of a redox couple, permeates into the solid-state structure usually through the porous metal electrode and sets up a reversible potential difference at that interface according to the reaction... 

Redox state — Redox state means the -> oxidation state of a compound or element In -> electrochemistry this term is also used to characterize the ratio of the oxidized to the reduced form of one redox species when both forms are present in a solution or solid compound. Frequently it is necessary to determine this ratio using electrochemical methods. For a fast and -> reversible electrode reaction Ox + ne Red the following techniques can be applied ... 

The main obstacle to creating liquid junction solar cells is photocorrosion of semiconductor electrodes, which reduces considerably their lifetime. In order to prevent, for example, anodic photocorrosion, a well-reversible redox couple is introduced into an electrolyte solution, so that the reaction of oxidation of the red component competes for photoholes with the reaction of photodecomposition of the electrode material (see Section IV.2). With the aid of this method, photocorrosion has been practically prevented in certain types of photocells and the duration of their continuous operation has been increased up to about one year. Yet, there are other, more subtle mechanisms of electrode degra-dation, which has hitherto prevented the lifetime of photoelectrochemical cells from becoming comparable with the 20-year lifetime of solid-state solar cells. 

Contents J,-H.Fuhrhop The Oxidation States and Reversible Redox Reactions of Metalloporphyrins. - G.Biauer Optical Activity of Conjugated Proteins. - T.J.R. Weakley Some Aspects of the Heteropolymolybdates and Heteropolytungstates. - A.Novak Hydrogen Bonding in Solids. Correlation of Spectroscopic and Crystallographic Data. 

The redox reaction of nickel hydroxide and nickel oxide hydroxide, the electrochemi-cally active compounds at the positive electrode of a nickel battery, was investigated. The thermodynamics of non-ideal solid solutions were applied to the reversible potential as a function of the state-of-discharge. In a temperature range 5 to 55°C two parameter activity coefficient models perform significantly better than one parameter models. 

Hashmi and Upadhyaya compared the electrochemical properties of the electrochemically synthesized MnO /PPy composite electrodes, fabricated with different electrolytes, namely polymer electrolyte film (polyvinyl alcohol [PVA]-HjPO aqueous blend), aprotic liquid electrolyte (LiClO -propylene carbonate [PC]), and polymeric gel electrolyte (poly methyl methacrylate [PMMA]-ethylene carbonate [EC]-PC-NaClO ) [60]. The cell with aqueous PVA-H PO showed non-capacitive behavior owing to some reversible chemical reaction of MnO with water, while the MnO / PPy composite was found to be a suitable electrode material for redox supercapacitors with aprotic (non-aqueous) electrolytes. The solid-state supercapacitor based on the MnO /PPy composite electrodes with gel... 

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