Fe2O3 Blocking Layer Produced by Cyclic Voltammetry Leads to Improved Photoelectrochemical Performance of Hematite Nanorods

Language
en
Document Type
Article
Issue Date
2022-10-20
First published
2019-02-19
Issue Year
2022
Authors
Poornajar, Mahshid
Nguyen, Nhat Truong
Ahn, Hyo-Jin
Büchler, Markus
Liu, Ning
Kment, Stepan
Zboril, Radek
Yoo, Jeong Eun
Schmuki, Patrik
Editor
Publisher
MDPI
Abstract

Hematite is a low band gap, earth abundant semiconductor and it is considered to be a promising choice for photoelectrochemical water splitting. However, as a bulk material its efficiency is low because of excessive bulk, surface, and interface recombination. In the present work, we propose a strategy to prepare a hematite (α-Fe2O3) photoanode consisting of hematite nanorods grown onto an iron oxide blocking layer. This blocking layer is formed from a sputter deposited thin metallic iron film on fluorine doped tin oxide (FTO) by using cyclic voltammetry to fully convert the film into an anodic oxide. In a second step, hematite nanorods (NR) are grown onto the layer using a hydrothermal approach. In this geometry, the hematite sub-layer works as a barrier for electron back diffusion (a blocking layer). This suppresses recombination, and the maximum of the incident photon to current efficiency is increased from 12% to 17%. Under AM 1.5 conditions, the photocurrent density reaches approximately 1.2 mA/cm2 at 1.5 V vs. RHE and the onset potential changes to 0.8 V vs. RHE (using a Zn-Co co-catalyst).

Journal Title
Surfaces
Volume
2
Issue
1
Citation
Surfaces 2.2 (2019): 131-144. <https://www.mdpi.com/2571-9637/2/1/11>
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