Rate Constants of Rate-Limiting Steps of the Water Splitting Reaction in Heterogeneous Bipolar Membranes Containing Catalyst Particles

A method has been developed for calculating the rate constants of rate-limiting steps of the water splitting reaction in the generating contacts of heterogeneous bipolar membranes (BPMs) containing particles of a catalytic additive. The method is based on the use of the equation of the current–voltage characteristic of the bipolar region of a heterogeneous BPM that contains generating contacts of two types. For the case when the catalytic additive is a cation exchanger (CE), one of the contacts is formed by CE particles and anion exchanger (AE) particles contained in BPM layers, and the other is formed by catalytic additive particles and AE particles contained in BPM layers. The order of the rate constants for the rate-limiting steps of the water splitting reaction in the studied membranes is consistent with the catalytic activity series, the constants of which are calculated based on the proton transfer reactions between water molecules and ionogenic groups contained in the BPM layers.