Coplanar interdigitated band electrodes for electrosynthesis. Part 4: Application to sea water electrolysis

Screen printing technology was here employed for the fabrication of interdigitated electrodes for sea water electrolysis. The anodes consisted of a ruthenium dioxide film printed on top of a thick film of platinum limiting the anodic formation of oxygen, whereas the cathodic bands are made of platinum ink. Despite the low inter-electrode gap (1 mm) and the electrode alignment, the production of hypochlorite from synthetic sea water in an agitated tank cell, could reach a current efficiency of 80% and conversion up to 30%. This geometry was found particularly suitable due to the enhanced mixing of the electrolyte between the anodes and the cathodes which resulted in a reduction of the scale deposition at the cathodes. Tarter was found to form on the cathodic bands but was rapidly released into the bulk solution, so that the array could be used over long periods of time. It has thus been shown that this cell configuration could be particularly interesting for preventing cathode passivation during electrolysis of sea water. (C) 1998 Elsevier Science Ltd. All rights reserved.