Investigation of FeNi alloy foams at high oxygen evolution reaction rates using a dry anode setup in alkaline environment

We investigated the composition-activity relationship of porous FeNi alloy foams for the alkaline oxygen evolution reaction (OER). We compared conventional transient behavior using cyclic voltammetry with the performance at high geometric current densities up to 3.0 A cm-2 achieved at quasi steady-state conditions employing pulsed electrolysis. The experiments were performed under setup parameters, we introduce as dry anode conditions for anion exchange membrane (AEM) water electrolyzers. In this context, a dry anode refers to an electrode setup in which the catalyst is not directly submerged in a liquid medium, unlike conventional electrodes fed with an alkaline electrolyte. Instead, the anode is purged with humidified gas. Eleven different compositions in the FeNi alloy space (93 – 2 at. % Fe) were synthesized using the hydrogen bubble template method, resulting in porous foams with similar structures. A rigorous statistical analysis of all measured data was conducted to ensure reproducibility. The influence of bubble formation on the solution resistance is elucidated and, consequently, the apparent performance is assessed. The most efficient alloy composition required an averaged mean potential of 1.82 VRHE for 3 A cm-2 under quasi steady-state conditions.