A facile approach for preparing densely-packed individual p-NiO/n-Fe2O3 heterojunction nanowires for photoelectrochemical water splitting

Singh, AK and Sarkar, D (2018) A facile approach for preparing densely-packed individual p-NiO/n-Fe2O3 heterojunction nanowires for photoelectrochemical water splitting. In: Nanoscale, 10 (27). pp. 13130-13139.

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Abstract

Innovative design of electrode materials is crucial for efficient conversion of solar energy into chemical fuel through photoelectrochemical (PEC) water splitting. Herein, we report the development of a p-n heterojunction nanowire (NW) based photoanode made of low cost earth-abundant materials. Densely-packed and freestanding individual p-NiO/n-Fe2O3 heterojunction NWs are fabricated through consecutive electrodeposition of Fe and Ni NWs inside the pores of the anodic alumina template followed by controlled oxidation. Heterojunction formation in individual NWs is confirmed through energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM), along with elemental mapping on individual NWs through electron energy loss spectroscopy (EELS). An inverted 'V' shape nature of the Mott-Schottky curve suggests p-n diode like characteristics of the heterojunction NWs. These p-n heterojunction NWs demonstrate a significantly enhanced photocurrent density (∼24 times at a potential of 1.23 V vs. RHE) and a cathodic shift (∼0.4 V) of the photocurrent onset potential compared to the pristine Fe2O3 NW electrode, which can be attributed to the synergistic combination of n-Fe2O3 with the co-catalyst p-NiO facilitating the generation and transfer of photogenerated holes into the electrolyte for water oxidation. This study validates the feasibility of developing Fe2O3 based heterojunction photoelectrodes for efficient PEC water splitting.

Item Type:	Journal Article
Publication:	Nanoscale
Publisher:	Royal Society of Chemistry
Additional Information:	The copyright for this article belongs to the Royal Society of Chemistry.
Keywords:	Alumina; Aluminum oxide; Anodic oxidation; Electrochemistry; Electrodes; Electrolytes; Electron energy levels; Electron scattering; Energy dispersive spectroscopy; Energy dissipation; Hematite; Heterojunctions; High resolution transmission electron microscopy; Nanowires; Nickel oxide; Photoelectrochemical cells; Semiconductor diodes; Solar energy; Transmission electron microscopy, Anodic alumina template; Controlled oxidations; Earth-abundant materials; Energy dispersive spectroscopies (EDS); Photocurrent density; Photoelectrochemical water splitting; Photoelectrochemicals; Synergistic combinations, Electron energy loss spectroscopy
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	07 Aug 2022 08:55
Last Modified:	07 Aug 2022 08:55
URI:	https://eprints.iisc.ac.in/id/eprint/75442

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