By creating an acidic microenvironment with Brønsted acid oxides, the system delivers high-purity hydrogen without the need for ultrapure water—paving the way for more practical and scalable clean energy solutions.
In recent years, energy engineers have been exploring sustainable methods to generate and store electricity, with hydrogen production via electrolysis emerging as a promising solution. Electrolyzers, powered by renewable energy sources like solar or wind, can split water into hydrogen and oxygen. The hydrogen produced can be used in fuel cells to generate electricity without combustion, offering clean energy solutions for heavy vehicles such as trucks and buses, as well as backup power for critical infrastructure like hospitals and data centers.
Proton exchange membrane (PEM) electrolyzers are among the most advanced technologies for hydrogen production. These devices use a special membrane that allows protons (H⁺) to pass through while blocking gases, resulting in high-purity hydrogen output. However, they are costly and typically require ultrapure water to prevent degradation from impurities, which limits their practical deployment.
To address this, researchers at Tianjin University and collaborating institutions developed a novel strategy to improve the tolerance of PEM electrolyzers to impure water. Their work, published in Nature Energy, introduces a modified catalyst that creates a more acidic microenvironment within the electrolyzer. This is achieved by incorporating Brønsted acid oxides, specifically MoO₃-x, into a platinum-carbon (Pt/C) cathode.
This innovation enables the electrolyzer to function effectively with tap water, maintaining high performance for over 3,000 hours at a current density of 1.0 A/cm²—comparable to systems using ultrapure water. By using advanced techniques like pH ultramicroelectrodes and scanning electrochemical microscopy, the researchers confirmed that the Brønsted acid oxide lowers the local pH at the cathode. This enhances hydrogen production kinetics, prevents the deposition of contaminants, and protects the membrane from degradation.
The study offers a significant advancement in PEM electrolyzer design, potentially reducing the need for costly water purification systems. These findings pave the way for the broader and more practical deployment of hydrogen energy systems, even in environments where only impure water sources are available. Future work may further refine this approach, making sustainable hydrogen production more accessible and economically viable.
