STTR Phase I: Dual-pH Water Splitting Device Comprising Earth-Abundant Electrocatalysts

This Small Business Innovation Research Phase I project will assess the commercial viability of using new non-precious metal catalysts to produce hydrogen by splitting water. Electrolyzers made with these new catalysts have the potential to deliver higher efficiencies and lower capital costs than currently available systems. The market for hydrogen today is $115 billion per year. Currently, hydrogen is primarily produced via steam reformation of methane. Hydrogen production via steam reformation emits millions of tons of CO2 into the atmosphere annually. There is broad agreement that water electrolysis can play a significant role in future hydrogen production if cost reductions can be realized. In addition, hydrogen has the potential to store energy produced by renewable energy systems like solar and wind and make it available on demand. The initial market entry point for these new electrolyzers is to supply hydrogen for fuel cell powered forklifts used in material handling. A life cycle cost analysis by the National Renewable Energy Laboratory (NREL) has shown that the total life cycle costs of hydrogen fuel cell forklifts are 10% cheaper than those using lead acid batteries. The intellectual merit of this project is focused on the ability of new earth-abundant non-precious metal catalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) to dramatically lower costs while improving efficiency in water splitting. The HER electrocatalyst is composed of hyper-thin FeS2 nano-discs and the OER electrocatalyst is nanoamorphous Ni0.8:Fe0.2 oxide. The preferred operating pH for the catalysts are different (pH 7 for the hyper-thin FeS2 nano-discs and pH 14 for the nanoamorphous Ni0.8:Fe0.2 oxide). Preliminary data shows that these two catalysts with the dual-pH membrane can effectively split water with a total overpotential of only 300 mV (1.53 V in a two electrode configuration). This is more than 50 mV lower than the best-known precious metal catalysts, Pt and IrOx, used in current commercial electrolyzers. The project will continue the optimization of these catalysts in the dual-pH electrolyzer stack and also determine if stability and lifetime meet commercial requirements This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.