DESC0024011

Water electrolysis is a zero-emission process to produce hydrogen with high efficiency. However, current water electrolysis technology depends on pure water feedstocks which makes the process expensive and a less viable option for widespread adoption. Impure water electrolysis can reduce the cost of water purification processes associated with water electrolysis. Despite its potential benefits, impure water electrolysis faces challenges such as chlorine evolution that reduce its performance and durability.This Small Business Innovative Research Phase I project will develop anion exchange membrane electrolyzers for impure water electrolysis to reduce the cost of hydrogen production. Anion exchange membrane electrolyzers have lower manufacturing and maintenance costs due to operation in alkaline conditions. In addition, oxygen evolution in alkaline conditions requires 480 mV less overpotential compared to chlorine evolution, which is beneficial for impure water operation.Phase I of this project will include developing a modified anode electrode and optimization of significant parameters of the anion exchange electrolyzer to achieve the current density of 1.5 A/cm2 (V<1.9 V) and low degradation rates (<4 mV/kh). For anode electrode modification, an ultra-thin anti-corrosive sublayer will be deposited under a highly active earth-abundant transition metal catalyst, and Cl– blocking overlayers will be added to the anode electrode to address low-performance and stability challenges in impure water electrolysis.The impure water electrolyzer developed in this project will reduce the cost and energy usage associated with water purification processes while preserving scarce freshwater resources. With abundant seawater resources and access to renewable energy, coastal arid regions have the potential to become ideal locations for hydrogen production. Additionally, electrofuels producers are targeting areas of high solar energy for production, but these areas are often tied to scarce potable water reserves, like the Southwest of the United States. Solving the technical difficulties around impure water operation would enable these important hydrogen markets.