Photoelectrochemical Sensing of Hydrogen Peroxide on Hematite

Due to its abundance and chemical stability, hematite (α‐Fe 2 O 3 ) is a promising n ‐type semiconductor photoelectrode. This is particularly true in the frame of the rapidly developing area of photoelectrochemical (PEC) sensing, where the short excited‐state lifetime and the small carrier diffusion length of hematite can be beneficially employed. On the other hand, H 2 O 2 is an essential molecule for biological, environmental and industrial applications. In this article, we report a simple method to prepare photoelectroactive hematite layers on fluorine‐doped SnO 2 (FTO) and we use these surfaces for H 2 O 2 PEC sensing. The so‐created sensors allow to reliably detect H 2 O 2 down to a sub‐μM concentration with a large linear range and a good reusability.