Efficient Photoelectrochemical Water Oxidation on Hematite with Fluorine‐Doped FeOOH and FeNiOOH as Dual Cocatalysts. Issue 21 (18th October 2018)

• Record Type: Journal Article
• Authors: Deng, Jiujun; Zhang, Qingzhe; Feng, Kun; Lan, Huiwen; Zhong, Jun; Chaker, Mohamed; Ma, Dongling
• Is Part Of: ChemSusChem. Volume 11:Issue 21(2018)
• Page Start: 3783
• Page End: 3789
• Publication Date: 2018-10-18
• Subjects: photoelectrocatalysis -- doping -- hematite -- iron -- water oxidation; Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.201801751
• Languages: English
• ISSNs: 1864-5631

Abstract

Abstract: An effective cocatalyst is usually required to improve the performance of photoelectrochemical (PEC) water splitting catalysts. A fluorine‐doped FeOOH (F:FeOOH) cocatalyst on a hematite photoanode was used to lower the onset potential by 140 mV and significantly improve the PEC performance. Moreover, a more effective dual cocatalytic system was prepared by subsequent loading of a FeNiOOH cocatalyst, which resulted in a further decrease of the onset potential by 270 mV. The final onset potential of the Fe2 O3 /F:FeOOH/FeNiOOH photoanode was lowered to 0.45 V versus the reversible hydrogen electrode (RHE), which is one of the lowest onset potential values ever reported for hematite photoanodes. The photocurrent also dramatically increased by a factor of approximately 3 to 0.9 mA cm −2 at 1.0 V versus RHE. Based on the structural, chemical, and electrochemical impedance spectroscopy characterization, the enhanced performance was attributed to the F:FeOOH overlayer, which reduced the surface recombination and accelerated the oxygen evolution reaction activity, and the FeNiOOH cocatalyst, which further enhanced the reaction kinetics. The facile preparation of the F:FeOOH cocatalyst and the design of the dual cocatalytic system will allow the development of high‐performance hematite photoanodes. Abstract : Two is better than one ! Fluorine‐doped FeOOH (F:FeOOH) and FeNiOOH were used as cocatalysts on a hematite photoanode to catalyze the oxygen evolution reaction (OER). The use of the cocatalysts lowered the onset potential by 270 mV and significantly improved the photoelectrochemical performance. The excellent performance originated from the reduced surface recombination and accelerated OER activity of F:FeOOH and the enhanced OER kinetics of FeNiOOH.