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Unveiling the Hydration Structure of Ferrihydrite for Hole Storage in Photoelectrochemical Water Oxidation
Author(s) -
Wang Pengpeng,
Li Deng,
Chi Haibo,
Zhao Yongle,
Wang Junhu,
Li Dongfeng,
Pang Shan,
Fu Ping,
Shi Jingying,
Li Can
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202014871
Subject(s) - ferrihydrite , crystal structure , molecule , calcination , chemistry , dehydration , crystallography , chemical physics , crystal (programming language) , catalysis , organic chemistry , adsorption , biochemistry , computer science , programming language
Ferrihydrite (Fh) has been demonstrated acting as a hole‐storage layer (HSL) in photoelectrocatalysis system. However, the intrinsic structure responsible for the hole storage function for Fh remains unclear. Herein, by dehydrating the Fh via a careful calcination, the essential relation between the HSL function and the structure evolution of Fh material is unraveled. The irreversible and gradual loss of crystal water molecules in Fh leads to the weakening of the HSL function, accompanied with the arrangement of inner structure units. A structure evolution of the dehydration process is proposed and the primary active structure of Fh for HSL is identified as the [FeO 6 ] polyhedral units bonding with two or three molecules of crystal water. With the successive loss of chemical crystal water, the coordination symmetry of [FeO 6 ] hydration units undergoes mutation and a more ordered structure is formed, causing the difficulty for accepting photogenerated holes as a consequence.