New, hydrophobic ionic liquids with low melting points (<-30 degrees C to ambient temperature) have been synthesized and investigated, based on 1,3-dialkyl imidazolium cations and hydrophobic anions. Other imidazolium molten salts with hydrophilic anions and thus water-soluble are also described. The molten salts were characterized by NMR and elemental analysis. Their density, melting point, viscosity, conductivity, refractive index, electrochemical window, thermal stability, and miscibility with water and organic solvents were determined. The influence of the alkyl substituents in 1, 2, 3, and 4(5)-positions on these properties was scrutinized. Viscosities as low as 35 cP (for 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)amide (bis(triflyl)amide) and trifluoroacetate) and conductivities as high as 9.6 mS/cm were obtained. Photophysical probe studies were carried out to establish more precisely the solvent properties of 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)amide). The hydrophobic molten salts are promising solvents for electrochemical, photovoltaic, and synthetic applications.

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In view of the use of organic electrolytes in solar energy conversion systems and the imminent need to minimize energy efficiency losses and performance limitations imposed on the system by iodine reduction on the counterelectrode, a catalyst was developed. The specific temperature regime and procedure described for the thermal decomposition of platinum‐chloride (platinum‐bromide or possibly other Pt compounds) from anhydrous isopropanol (or possibly other organic solvents) produces an electrode interface that is a selective catalyst for iodine/triiodide reduction in organic electrolytes, matching the kinetics reported in aqueous iodide/iodine systems. This technology produces catalytic electrodes that are electrochemically/chemically stable in their operating environment, in addition to providing superior mechanical endurance or robustness ana good adherence to substrates. The catalyst has been structurally characterized as nanosized platinum metal clusters. The very low platinum loadings (less than 3 μg/cm2) render these electrodes optically transparent, and economy in the quantity of platinum used is an additional advantage. The technology can be applied to all solar energy conversion systems utilizing the iodide/triiodide redox couple as mediator or any iodide/triiodide‐mediated electrochemical device involving, e.g., electrochromism, charge generation (fuel cells), or storage.

If we define Pp, as follows then Eq. A-3 could be rewritten as v,But the species extent of reaction, E, is defined as e = l -y By substituting for y in A-6 using A-5 and solving for P,,, we obtain Thus, Pp, will be equal to the traditional "fraction of unreacted species" (1 -E) when there is no volume change or dilution of initial electrolyte tank volume. Conceptually, pPu is proportional to (1 -e) where the constant of proportionality is the extent of dilution resulting from water transport. This performance criteria should not be confused with (1 -e). REFERENCES 1. D. T. Hobbs, in Electrochemistry for a Cleaner Environment, J. D. Genders and N. L. Weinberg, Editors, The

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