University of Pittsburgh chemical engineer John Keith and his collaborators at Drexel University and Brookhaven National Laboratory have taken a practical step toward improving on-site ozone production for water disinfection. Their recent study examines why one of the most promising catalyst materials for electrochemical ozone generation degrades quickly, and how future designs might avoid that failure.
Alaufey, R., Zhao, L., Lents, C., Markunas, B., Walter, A. D., Wu, Q., Keith, J. A., & Tang, M. (2025). Electrochemical Corrosion and Catalysis Dynamics of Tin Oxide during Water Oxidation. ACS Catalysis, 15(21), 18601–18611. https://doi.org/10.1021/acscatal.5c04461
Interest in ozone as a disinfectant has grown as facilities look for alternatives to chlorine, which is effective but difficult to store and transport safely. Chlorine can also form unwanted byproducts that limit its use in some environments. Ozone, by contrast, can be generated on demand in water and breaks down into oxygen, leaving no long-term chemical residue. The challenge has been finding a catalyst that produces ozone efficiently through water electrolysis while maintaining stability under the high voltages required.
John Keith from University of Pittsburgh stated,
“This work is a testament to how fundamental science and engineering come together to answer long-standing questions and concoct new routes to improved water sanitation technologies”.
The research team focused on nickel and antimony doped tin oxide, a material long considered one of the safest and most cost-effective catalyst options for electrochemical ozone production. In practice, however, this catalyst loses activity far too quickly. By combining computational chemistry with experimental work, the researchers identified the specific surface features that initially make the catalyst effective but ultimately cause it to deteriorate.
Quantum-chemical modeling revealed that structural defects on the catalyst surface accelerate the electron transfer needed to form ozone. These same defects also make the surface vulnerable to corrosion once water molecules attach and reorganize into reactive networks. This local chemistry lowers the pH at the surface and causes tin atoms to dissolve into the electrolyte, gradually destroying the catalyst. Measurements of electronic structure and corrosion pathways, along with microscopy images collected after extended operation, supported these findings. Interestingly, the team observed that reactive oxygen species, which are often assumed to cause degradation, played a comparatively minor role. Most of the damage came directly from interactions between the catalyst and water under strongly oxidizing conditions.
The work outlines a clearer set of design considerations for improving catalyst longevity. Future materials will need to preserve the beneficial defect-driven ozone-formation pathway while preventing the same sites from triggering corrosion. Achieving this may require new compositions, selective doping strategies, protective surface treatments, or electrochemical environments that stabilize the catalyst during operation.
Although electrochemical ozone production is not yet ready to replace chlorine at scale, the study provides a necessary explanation of where current catalysts fail and how those weaknesses might be addressed. Instead of treating degradation as an unavoidable limitation, the research maps out a solvable engineering problem. With better-designed catalysts, on-site ozone generation could become a safer and more flexible disinfection option for hospitals, small water systems, and facilities that cannot rely on chlorine storage.
For Keith and his colleagues, the work represents a gradual but meaningful move toward practical ozone-based sanitation. By connecting fundamental surface chemistry with device-level performance, they have given future engineers a clearer path toward systems that produce disinfecting ozone reliably, without creating new safety concerns or expensive maintenance demands.
Adrian graduated with a Masters Degree (1st Class Honours) in Chemical Engineering from Chester University along with Harris. His master’s research aimed to develop a standardadised clean water oxygenation transfer procedure to test bubble diffusers that are currently used in the wastewater industry commercial market. He has also undergone placments in both US and China primarely focused within the R&D department and is an associate member of the Institute of Chemical Engineers (IChemE).
