Performance of single chamber biocatalyzed electrolysis with different types of ion exchange membranes

In this paper hydrogen production through biocatalyzed electrolysis was studied for the first time in a single chamber configuration. Single chamber biocatalyzed electrolysis was tested in two configurations: (i) with a cation exchange membrane (CEM) and (ii) with an anion exchange membrane (AEM). Both configurations performed comparably and produced over 0.3 m(3) H-2/m(3) reactor liquid volume/day at 1.0V applied voltage (overall hydrogen efficiencies around 23%). Analysis of the water that permeated through the membrane revealed that a large part of potential losses in the system were associated with a pH gradient across the membrane (CEM Delta pH = 6.4; AEM Delta pH = 4.4). These pH gradient associated potential losses were lower in the AEM configuration (CEM 0.38 V, AEM 0.26V) as a result of its alternative ion transport properties. This benefit of the AEM, however, was counteracted by the higher cathode overpotentials occurring in the AEM configuration (CEM 0.12 Vat 2.39 A/m(2); AEM 0.27 V at 2.15 A/m(2)) as a result of a less effective electroless plating method for the AEM membrane electrode assembly (MEA). (c) 2007 Elsevier Ltd. All rights reserved.