A cost-effective electrocatalyst for oxygen evolution reaction in PEM water electrolysis

A non-platinum group metal (non-PGM) anode catalyst based on silver and titanium suboxide was prepared and used for the oxygen evolution reaction in a PEMWE cell. The large increase of the Iridium cost recently observed requires individuating alternative catalyst solutions for the oxygen evolution reaction (OER) in PEMWE. The electrocatalyst under study was prepared by using a solid – state synthesis procedure, starting from silver nitrate and titanium suboxides with Magneli phase with a following thermal treatment at 300 °C in a 50% H2/N2 gas stream to promote inclusion of silver within the Ti – suboxides structure. Here, a membrane – electrode assembly (MEA), consisting of Ag/TinO2n-1 and Pt/C spray coated on both sides of a 212 Nafion membrane (thickness 50 μm), was investigated in a 5 cm2 single cell, in order to evaluate the performance and durability of the novel anodic electrocatalyst in acid environment. Electrochemical tests, consisting of polarization curves and impedance spectroscopy analysis performed before and after 1000 h steady state test have shown promising results compared to PGM – free catalyst- based alkaline systems. Encouraging performance have observed at 80°C, reaching 0.6 A cm2 at 2 V and 2 A cm2 at 2.2 V in IR-free curves. Post operation analysis showed an increase of the oxidation states for Ag and Ti.