期刊
CHEMICAL ENGINEERING SCIENCE
卷 250, 期 -, 页码 -出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.ces.2021.117397
关键词
Photoelectrochemical; Hematite; Oxygen vacancies; Surface states
资金
- National Natural Science Foundation of China [21978200, 22161142002, 22008170]
- Scientific Research Projects of the Ministry of Education of China [6141A02033522]
In this study, a secondary calcination strategy was developed to regulate the density and distribution of surface states in the hematite photoanode system, resulting in effective suppression of carrier recombination and reduction of kinetic overpotential, leading to improved photoelectrochemical efficiency.
Sluggish interfacial carrier transfer and oxygen production kinetics of photoelectrochemical water split-ting are related to the Fermi-level pinning of the hematite surface states, thus it requires extra energy input and results in low PEC efficiency. Here we develop a facile secondary calcination strategy for regulating the density and distribution of surface states in hematite photoanode system. The fabricated alpha- Fe2O3-450 possesses significantly reduced disordered layers and renovated surface oxygen vacancy structure to increase carrier density and effectively passivate surface trapping states. Thus, both bulk and interfacial recombination of electrons and holes are effectively suppressed, and the quasi-hole Fermi level moves to more positive position, leading to a large photovoltage for reducing kinetic overpotential. Therefore, the photocurrent density of alpha-Fe2O3-450 (1.035 mA cm(-2)) is 1.8 times higher than that of pristine alpha-Fe2O3 (0.58 mA cm(-2)) at 1.23 V versus reversible hydrogen electrode, and alpha-Fe2O3-450 has more cathodic onset potential than alpha-Fe2O3. (C) 2021 Elsevier Ltd. All rights reserved.
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