Long-term durability of metastable β-Fe<sub>2</sub>O<sub>3</sub> photoanodes in highly corrosive seawater.

Liu, Changhao; Zhang, Ningsi; Li, Yang; Fan, Rongli; Wang, Wenjing; Feng, Jianyong; Liu, Chen; Wang, Jiaou et al. · Nat Commun · 2023

basic_science · Level V

Where this comes from

Abstract

Durability is one prerequisite for material application. Photoelectrochemical decomposition of seawater is a promising approach to produce clean hydrogen by using solar energy, but it always faces the problem of serious Cl<sup>-</sup> corrosion. We find that the main deactivation mechanism of the photoanode is oxide surface reconstruction accompanied by the coordination of Cl<sup>-</sup> during seawater splitting, and the stability of the photoanode can be effectively improved by enhancing the metal-oxygen interaction. Taking the metastable β-Fe<sub>2</sub>O<sub>3</sub> photoanode as an example, Sn added to the lattice can enhance the M-O bonding energy and hinder the transfer of protons to lattice oxygen, thereby inhibiting excessive surface hydration and Cl<sup>-</sup> coordination. Therefore, the bare Sn/β-Fe<sub>2</sub>O<sub>3</sub> photoanode delivers a record durability for photoelectrochemical seawater splitting over 3000 h.