Bifunctional citrate-Ni 0.9 Co 0.1 (OH) x layer coated fluorine-doped hematite for simultaneous hole extraction and injection towards efficient photoelectrochemical water oxidation.

Autor: Wang P; State Key Laboratory of Applied Organic Chemistry (SKLAOC), The Key Laboratory of Catalytic Engineering of Gansu Province, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu 730000, P. R. China. jinjun@lzu.edu.cn., Li F, Long X, Wang T, Chai H, Yang H, Li S, Ma J, Jin J
Jazyk: angličtina
Zdroj: Nanoscale [Nanoscale] 2021 Sep 07; Vol. 13 (33), pp. 14197-14206. Date of Electronic Publication: 2021 Aug 12.
DOI: 10.1039/d1nr03257g
Abstrakt: Surface modification by loading a water oxidation co-catalyst (WOC) is generally considered an efficient means to optimize the sluggish surface oxygen evolution reaction (OER) of a hematite photoanode for photoelectrochemical (PEC) water oxidation. However, the surface WOC usually exerts little impact on the bulk charge separation of hematite. Herein, an ultrathin citrate-Ni 0.9 Co 0.1 (OH) x [Cit-Ni 0.9 Co 0.1 (OH) x ] is conformally coated on the fluorine-doped hematite (F-Fe 2 O 3 ) photoanode for PEC water oxidation to simultaneously promote the internal hole extraction and surface hole injection of the target photoanode. Besides, the conformally coated Cit-Ni 0.9 Co 0.1 (OH) x overlayer passivates the redundant surface trap states of F-Fe 2 O 3 . These factors result in a superior photocurrent density of 2.52 mA cm -2 at 1.23 V versus a reversible hydrogen electrode (V vs. RHE) for the target photoanode. Detailed investigation manifests that the hole extraction property in Cit-Ni 0.9 Co 0.1 (OH) x is mainly derived from the Ni sites, while Co incorporation endows the overlayer with more catalytic active sites. This synergistic effect between Ni and Co contributes to a rapid and continuous hole migration pathway from the bulk to the interface of the target photoanode, and then to the electrolyte for water oxidation.
Databáze: MEDLINE