PEM water electrolyser based on S-TiO2 Nafion membrane and IrRuOx electrocatalyst

Proton exchange membrane (PEM) water electrolysis is considered the most promising method to produce hydrogen with a high degree of purity from renewable energy resources. The process is characterized by high efficiencies and suitable current density even at moderate temperatures. PEM electrolysis systems have a number of advantages in comparison to the traditional alkaline electrolysers, such as ecological cleanliness, considerably smaller mass-volume characteristics, no corrosive electrolyte is involved, low maintenance and, essentially, a high degree of gas purity [1]. The main disadvantage of PEM electrolysis is the high energy loss, which is mainly due to the use of oxygen evolution electrode overpotential and polymer electrolyte membrane resistance. It is therefore crucial to develop optimal oxygen-evolving electro-catalysts and highly conductive, mechanically robust membranes in order to minimize energy loss and enhance system durability. This work reports on a hybrid solid-state membrane based on sulfated titania nanoparticles as low-cost proton conductors for PEM water electrolyser applications [2-3]. The influence of the inorganic filler in the properties of composite Nafion membranes is investigated in a single cell, adopting in-house synthesized IrRuOx electrocatalysts, in a temperature range from 25° to 90°C. A comparison between bare and composite polymer electrolyte is discussed in terms of linear sweep voltammetry and electrochemical impedance spectroscopy measurements.