Ion-Conductive and Transparent Resorcinol-Formaldehyde Hydrogels for Electrochemical and Solar Applications

Resorcinol-formaldehyde hydrogels equilibrated with concentrated liquid electrolytes show high ion-conductivities (up to 24 mS.cm(-1) for HCl-equilibrated hydrogel). Conventional electrochemistry can be conducted with electrodes cast in these hydrogels, serving as quasi-solid electrolytes. The hydrogels are also transparent, which makes them good candidates for application in light induced processes. The present paper demonstrates this use for the photoelectrochemical splitting of water. Hydrogel films, consisting of alpha-Fe2O3 hematite and hydroquinone, serve as catalytic films for the photoanodic oxidation of water. The illumination maximum effect at pH 6 and 12 is obtained at biased potentials of +0.5 and +0.3 V vs. Ag/AgCl, respectively. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.014201esl] All rights reserved.