A recent communication published in Advanced Energy Materials reported an AEM electrolyzer, which delivers 1.0 A cm−2 at 1.57 V at 80 °C in 1 M KOH. The energy conversion efficiency at this current density is as high as 75%. This efficiency is the highest among all AEM electrolyzers, including those employing noble-metal catalysts. The most efficient ever alkaline water electrolyzer use Sustainion® membrane with novel non-noble catalysts.
The work is made possible using novel judiciously processed NiMo oxide catalysts along with high conducting Sustainion® AEM at the heart of the device. Processing of these the catalyst in mixed NH3/H2 atmosphere results in a NiMo-NH3/H2 catalyst, which has superior activity in HER, delivering 500 mA cm−2 at an overpotential of 107 mV. Doping Fe ions into the NiMo-NH3/H2 catalyst yields an Fe-NiMo-NH3/H2 catalyst, which is highly active for the OER, delivering 500 mA cm−2 at an overpotential of 244 mV. TEM and HRTEM images of the Fe-NiMo-NH3/H2 catalyst after anodic activation are shown below:
This work demonstrates the potential of earth-abundant electrocatalysts in water splitting devices and provides a benchmark for AEM electrolyzers.
To take advantage of the highly conductive Sustainion® AEM and XA-9 Sustainion® Ionomer along with full electrolyzers and parts, visit the Dioxide Materials webstore and place an order.
Sustainion® membranes have shown superior performance in numerous studies. For examples this Nature Research uses Sustainion® to convert CO2 to 100% Formic Acid.