Catalysis of water splitting reaction in asymmetric bipolar membranes with different chemical composition of cation-exchange layer

Abstract

ABSTRACT The asymmetric bipolar membranes were prepared based on the heterogeneous anion-exchange membrane RALEX AMH and homogeneous perfluorocarbon cation-exchange film MF-4SC. A water-splitting catalyst was introduced into the cation-exchange layer of the membrane to investigate the course of the water-splitting reaction. The resulting membranes have been studied by electro-chemical impedance and voltamperometry methods. Effective water-splitting constants were calculated using the mathematical model of heterolytic water-splitting reaction developed previously. It is shown that introduction of the catalyst significantly reduces the voltage on the bipolar region but simultaneously increases the co-ion leakage. It was found that it is possible to regulate the fluxes of salt ions and water-splitting products (hydrogen and hydroxyl ions) by changing the current density. Such an ability makes it possible to conduct a desalting process with simultaneous pH adjustment.