WS2 nanosheets functionalized Fe2O3 nanorod arrays as a type II heterojunction for photoelectrochemical water splitting

Abstract

Fe2O3 is a stable and low bandgap photocatalyst capable of absorbing a wide range of solar spectra. However, a shorter hole diffusion length impedes its performance as an efficient photocatalyst. The formation of a type II heterojunction is an effective approach to facilitate the quick separation of photogenerated carriers. In this work, we report photo-electrochemical characteristics of WS2 functionalized Fe2O3 nanorod arrays fabricated on FTO coated glass substrate. The Fe2O3 nanorods fabricated by chemical bath deposition and WS2 nanosheets by the hydrothermal technique are characterized by X-ray diffraction, scanning and transmission electron microscopy, energy dispersive X-ray analysis (EDS), X-ray photoelectron spectroscopy, optical absorption, Raman spectra, and FT-IR. A heterojunction architecture formed between these resulted in a higher photocurrent density compared to that of bare Fe2O3 nanorods. Electrochemical impedance spectroscopy and Mott-Schottky measurements reveal lower charge transfer resistance and higher interfacial charge density for WS2 functionalized Fe2O3 nanorods. An energy band diagram for the heterojunction has been proposed to show the charge separation at the interface.

Keywords

• Fe2O3
• Nanorod
• WS2
• Nanosheet
• Heterojunction
• Photoelectrochemical