Ultrasonication-assisted liquid-phase exfoliation enhances photoelectrochemical performance in α-Fe2O3/MoS2 photoanode

Zohreh Masoumi; Meysam Tayebi; Byeong-Kyu Lee

doi:10.1016/j.ultsonch.2020.105403

Ultrasonication-assisted liquid-phase exfoliation enhances photoelectrochemical performance in α-Fe₂O₃/MoS₂ photoanode

Ultrason Sonochem. 2021 Apr:72:105403. doi: 10.1016/j.ultsonch.2020.105403. Epub 2020 Dec 7.

Authors

Zohreh Masoumi¹, Meysam Tayebi², Byeong-Kyu Lee³

Affiliations

¹ Department of Civil and Environment Engineering, University of Ulsan, Daehakro 93, Namgu, Ulsan 44610, Republic of Korea.
² Department of Civil and Environment Engineering, University of Ulsan, Daehakro 93, Namgu, Ulsan 44610, Republic of Korea. Electronic address: mtayebi2900@gmail.com.
³ Department of Civil and Environment Engineering, University of Ulsan, Daehakro 93, Namgu, Ulsan 44610, Republic of Korea. Electronic address: bklee@ulsan.ac.kr.

Abstract

This study successfully manufactured a p-n heterojunction hematite (α-Fe₂O₃) structure with molybdenum disulfide (MoS₂) to address the electron-hole transfer problems of conventional hematite to enhance photoelectrochemical (PEC) performance. The two-dimensional MoS₂ nanosheets were prepared through ultrasonication-assisted liquid-phase exfoliation, after which the concentration, number of layers, and thickness parameters of the MoS₂ nanosheets were respectively estimated by UV-vis, HRTEM and AFM analysis to be 0.37 mg/ml, 10-12 layers and around 6 nm. The effect of heterojunction α-Fe₂O₃/MoS₂ and the role of the ultrasonication process were investigated by the optimized concentration of MoS₂ in the forms of bulk and nanosheet on the surface of the α-Fe₂O₃ electrode while measuring the PEC performance. The best photocurrent density of the α-Fe₂O₃/MoS₂ photoanode was obtained at 1.52 and 0.86 mA.cm^-2 with good stability at 0.6 V vs. Ag/AgCl under 100 mW/cm² (AM 1.5) illumination from the back- and front-sides of α-Fe₂O₃/MoS₂; these values are 13.82 and 7.85-times higher than those of pure α-Fe₂O₃, respectively. The results of electrochemical impedance spectroscopy (EIS) and Mott-Schottky analysis showed increased donor concentration (2.6-fold) and decreased flat band potential (by 20%). Moreover, the results of IPCE, ABPE, and OCP analyses also supported the enhanced PEC performance of α-Fe₂O₃/MoS₂ through the formation of a p-n heterojunction, leading to a facile electron-hole transfer.

Keywords: 2D material; Sonochemistry; Transition-metal dichalcogenides (TMD); Ultrasonic; Ultrasonication-assisted synthesis; α-Fe(2)O(3)/MoS(2).