Wang Pengpeng, Li Deng, Chi Haibo, Zhao Yongle, Wang Junhu, Li Dongfeng, Pang Shan, Fu Ping, Shi Jingying, Li Can
State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Angew Chem Int Ed Engl. 2021 Mar 15;60(12):6691-6698. doi: 10.1002/anie.202014871. Epub 2021 Feb 10.
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 ] polyhedral units bonding with two or three molecules of crystal water. With the successive loss of chemical crystal water, the coordination symmetry of [FeO ] hydration units undergoes mutation and a more ordered structure is formed, causing the difficulty for accepting photogenerated holes as a consequence.
水铁矿（Fh）已被证明在光电催化系统中可作为空穴存储层（HSL）。然而，Fh负责空穴存储功能的内在结构仍不清楚。在此，通过仔细煅烧使Fh脱水，揭示了Fh材料的HSL功能与结构演变之间的本质关系。Fh中结晶水分子的不可逆且逐渐损失导致HSL功能减弱，同时伴随着内部结构单元的排列。提出了脱水过程的结构演变，并且确定Fh用于HSL的主要活性结构为与两到三个结晶水分子结合的[FeO]多面体单元。随着化学结晶水的相继损失，[FeO]水合单元的配位对称性发生突变并形成更有序的结构，结果导致难以接受光生空穴。
