New tech lets electrolyzers use impure water to make clean hydrogen

Researchers from Tianjin University and other Chinese institutes have developed a novel method enabling proton exchange membrane (PEM) electrolyzers to operate effectively using impure water, addressing a key limitation of current green hydrogen production technologies. Unlike alkaline electrolyzers, PEM electrolyzers produce higher purity hydrogen suitable for fuel cells but require ultrapure water, as impurities can degrade the membrane and increase costs. The new approach involves creating an acidic microenvironment at the cathode by adding Bronsted acid oxide (MoO3-x), which acts as a catalyst and locally lowers pH, enhancing electrolyzer performance and durability even with tap water. This innovation was validated through advanced microscopy techniques, showing that the PEM electrolyzer maintained stable operation for over 3,000 hours at a current density of 1.0 A/cm² using impure water, with performance comparable to conventional PEM systems relying on ultrapure water. By reducing the need for costly water pretreatment and extending system lifetime, this advancement could significantly lower the costs and complexity