High-Efficiency Anion Exchange Membrane Water Electrolysis Employing Non-Noble Metal Catalysts

Alkaline anion exchange membrane (AEM) water electrolysis is a promising technology for producing hydrogen using renewable energies. However, current AEM electrolyzers still employ noble-metal-containing electrocatalysts, or have significant overpotential loss, or both. Here non-noble-metal electrocatalysts for both the hydrogen and oxygen evolution reactions (HER and OER) are developed. Both catalysts are made of a same NiMo oxide. Judicious processing of these materials in a mixed NH3/H(2)atmosphere results in a NiMo-NH3/H(2)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/H(2)catalyst yields an Fe-NiMo-NH3/H(2)catalyst, which is highly active for the OER, delivering 500 mA cm(-2)at an overpotential of 244 mV. These catalysts are integrated into an AEM electrolyzer, which delivers 1.0 A cm(-2)at 1.57 V at 80 degrees C in 1mKOH. The energy conversion efficiency at this current density is as high as 75%. This work demonstrates high-efficiency AEM electrolysis using earth-abundant catalytic materials.