The effect of cationic impurities on PEM electrolither performance. A, B, polarization curve (a) and chronopotentiometric tests at 1.0 cm-2(b) on Pt/C || IRO2 electrolither provided DI water containing Na+, Ca2+ or Fe3+ ions. In A and B, curves of PEM electrolytic agents operating in DI water are included for reference. Catalytic Loading of PT/C || IRO2 Electroliser: 2 mgpt/c per 2 mgpt/c (mgpt/c cm -2; 0.4 mgpt cm -2) and 0.5 mgitro2 cm2. C, Schematic diagram of the binding of the pH ultra-large electrode with SECM to monitor the in situ pH of the PT/C catalyst layer (CL). Note that feedwater was fed to both sides and the anode and cathode water was mixed during electrolyzer operation. D, phcathode values measured at different current densities at a fixed distance of 1 μm between the pH and the catalyst layer. All values are expressed as mean ± standard deviation (SD). The error bars show the SDs of three measurements. E,phcathode was scanned at 0.5 cm -2 in the x-y plane over an area of 100 μm x 100 μm. f, Transmembrane mobility of Na+, Ca2+ and Fe3+ when electrical agent is operated at 1.0 cm-2. Credit: Wang et al. (Nature Energy, 2025).
In recent years, energy engineers have worked on a wide range of technologies that help generate and store electricity more sustainably. These include devices that can be used via processes where hydrogen (H2) and oxygen (O2) are decomposed into hydrogen (H2O) and oxygen (O2) using electricity provided via electrolytic agents, solar power, wind turbines or other energy technologies.
Hydrogen produced by electrolytic factors can be used in fuel cells, devices that convert the chemical energy of hydrogen into electricity without combustion, and can power trucks, buses, forklifts and various other heavy vehicles, as well as provide backup power to hospitals, data centers and other facilities.
Many recently designed electrolytic agents encourage the use of proton exchange membranes (PEMs) to split water into hydrogen. This allows the gas to be blocked, while still allowing the protons (H+) to pass through.
PEM electrolytic factors have been found to produce hydrogen at a higher purity compared to those produced by the most employed alkaline electrolyzers today. Nevertheless, they are more expensive and require ultrapure water. Impurities (e.g., positively charged ions, negatively charged ions, and other contaminants) will help the device degrade rapidly over time.
Researchers at Tianjin University and other laboratories have recently devised strategies to improve the catalysts of PEM electrolyzers, allowing impure water to be split.
Their strategy, outlined in a paper published in Nature Energy, involves creating an acidic microenvironment in PEM electrolyzers by modifying the cathode catalyst layers using a class of compounds called Brønsted oxides.
“PEM electrolyzers usually use UltraPia water as a raw material, as water supply, and in particular trace contaminants with cationic impurities, can cause failure.”
“The development of PEM electrolyzers that can withstand low purity water can minimize water pretreatment, reduce maintenance costs and extend system life.
“In this context, we have developed a microenvironmental ph-Regulated PEM electrolytic factor that can operate steadily in impure (“tap”) water at the current density of 1.0 cm-2.
To assess the potential of their strategy, Wang, Yang, and colleagues added Brønsted oxide MOO3-X to a cathode made of platinum and carbon (PT/C). They discovered that when integrated into PEM electrolyzers as catalysts, this cathode improves performance and can reliably generate hydrogen from impure water without rapidly decomposition over time.
“We used a combination of pH ultramicroelectrode and scan electrochemical microscopy to monitor local pH conditions in situ and discovered that brønsted acid oxide can lower the local pH.”
“In this way, we introduced Brønsted oxidized oxide MOO3-X into the PT/C cathode to create a highly acidic microenvironment that increases the rate of hydrogen production, inhibits deposition/precipitation at the cathode, and inhibits membrane degradation.”
This study can open up new and exciting possibilities for PEM electrolyzer design. This is because it can help reduce reliance on ultra-pure water and make it easier to deploy in a real setting.
In the future, other energy engineers could build on the team’s findings to develop other PEM electrolytic agents that can reliably divide impure water into hydrogen.
Written for you by author Ingrid Fadelli, edited by Sadie Harley and fact-checked and reviewed by Andrew Zinin. This article is the result of the work of a careful human being. We will rely on readers like you to keep independent scientific journalism alive. If this report is important, consider giving (especially every month). You will get an ad-free account as a thank you.
Details: Ruguang Wang et al, cathode catalyst layer was modified with Brønsted acid oxide to improve proton exchange membrane electrolither due to impure moisture cracking, natural energy (2025). doi:10.1038/s41560-025-01787-9
©2025 Science X Network
Quote: Convert tap water to hydrogen: New strategies allow PEM electrolyzers to use impure water (June 26, 2025) June 26, 2025 https://techxplore.com/news/2025-06-hydrogen-strategy-pem-electrolyzers-impure.htmll
This document is subject to copyright. Apart from fair transactions for private research or research purposes, there is no part that is reproduced without written permission. Content is provided with information only.
