Unlocking peroxide activation initiated by a solid-water interface

Activation of the peroxide (O–O) bond at a solid-liquid interface is a key aspect of biological and chemical oxidation reactions due to its fundamental role. An oxidation mechanism exemplified by typical Fenton-like persulfate-based heterogeneous oxidation, in which electron transfer dominates, is almost universally accepted. However, we present experimental results that challenge this view. At a solid-liquid interface, we show that protons are thermodynamically coupled to electrons. In situ quantitative titration yielded direct experimental evidence that the coupling ratio of protons to transferred electrons was 1:1, indicating a net proton-coupled electron transfer in which both the proton and electron enter the redox cycle. These findings will inform future developments in peroxide activation technologies, enabling more efficient redox activity via tight coupling of protons and electrons.