Towards hydrogen production using a breathable electrode structure to directly separate gases in the water splitting reaction

A novel electrode design to directly separate the gases and improve the efficiency of the water splitting reaction is described. In this work, platinum was used as a model catalyst, deposited on porous membranes with different pore size and shape. The O2 evolution rate was monitored at the gaseous side of these breathable electrodes. We show that the hydrophobic Goretex® membrane electrodes provide a highly efficient removal of the gases, breathing out 92% of expected O2 during water splitting, and thereby also largely avoiding the well known migration of oxygen to the cathode in the absence of a separator in the cell. The breathable structure is also shown to operate as a hydrogen electrode. The ability to separate the two gases, without the need for a separator, decreases gas cross-over and thereby enhances the coloumbic efficiency. Merging this approach with catalysts and photocatalysts of a variety of types e.g. non-precious metal and metal oxides will allow fabrication of cost efficient and straightforward water splitting devices.

► A breathable structure to directly separate gases in the water splitting reaction. ► Efficient separation of O2 and H2 from water splitting. ► 92% Faradaic efficiency is achieved without use of any separator. ► This novel design can be adopted for various water splitting catalysts.