Comment on “Radical-mediated proton transfer enables hydroxyl radical formation in charge-delocalized water” by R. Zhao, Q. Zhang, N. Yang, L. Li, Z. Li and C. Cui, Chem. Sci. , 2025, 16 , 11954 | Synapse
April 10, 2026Open Access
Comment on “Radical-mediated proton transfer enables hydroxyl radical formation in charge-delocalized water” by R. Zhao, Q. Zhang, N. Yang, L. Li, Z. Li and C. Cui, Chem. Sci. , 2025, 16 , 11954
Key Points
To critique the claims made by Cui and colleagues regarding the formation of hydroxyl radicals in low pH water.
Analyzed the thermodynamics of proton transfer processes.
Evaluated the conditions under which hydroxyl radicals might form.
Commented on the theoretical implications of charge-delocalized water and radical formation.
Challenged the spontaneous formation of hydroxyl radicals at pH below 4.
Demonstrated that proton transfer does not lead to the formation of hydroxyl radicals under claimed conditions.
Indicated that claims lack thermodynamic support.
Abstract
Cui and coworkers claim that H 2 O˙ + and HO˙ are formed spontaneously by lowering the pH to below 4. This is thermodynamically most unlikely. Thus, proton transfer does not involve HO˙.