Enhanced photoelectrochemical performance of an
a-Fe
2
O
3
nanorods photoanode with embedded
nanocavities formed by helium ions implantation
Hengyi Wu
a
, Liang Wu
a
, Shaohua Shen
b
, Yichao Liu
a
, Guangxu Cai
a
,
Xuening Wang
a
, Yunhang Qiu
a
, Huizhou Zhong
a
, Zhuo Xing
a
,
Jun Tang
a
, Zhongqin Dai
a
, Changzhong Jiang
a
, Feng Ren
a,*
a
School of Physics and Technology, Center for Ion Beam Application, Hubei Key Laboratory of Nuclear Solid Physics,
Wuhan University, Wuhan, 430072, China
b
International Research Center for Renewable Energy and State Key Laboratory of Multiphase Flow in Power
Engineering, Xi'an Jiaotong University, Shanxi, 710049, China
highlights
The photoelectrochemical performance of a-Fe
2
O
3
photoanode was enhanced through controlled He
þ
ion implantation.
The size and density of nanocavities in the a-Fe
2
O
3
nanorods can be tailored by controlling the ion fluences.
Nanocavities can increase the separation efficiency of electron-hole pairs.
article info
Article history:
Received 26 June 2019
Received in revised form
31 December 2019
Accepted 24 January 2020
Available online xxx
Keywords:
a-Fe
2
O
3
Nanocavities
PEC water splitting
Ion implantation
abstract
Hematite is a prospective semiconductor in photoelectrochemical (PEC) water oxidation
field due to its suitable bandgap for the solar spectrum absorption. Nevertheless, the low
transfer and separation efficiency of the charge carriers are restricted by its diffusion
length of hole which is 2e4 nm and further reduce the PEC performance. Here, we report an
innovative method, by introducing nanocavities into the a-Fe
2
O
3
nanorod arrays photo-
anodes through helium ions implantation, to improve the charge carriers' transfer and
separation efficiency and further to enhance water oxidation performance. The result in-
dicates that, the photocurrent density of nanocavities embedded a-Fe
2
O
3
photoanode (S2-A
sample) reaches 1.270 mA/cm
2
at 1.6 V vs. RHE which is 1-fold higher than that of the
pristine a-Fe
2
O
3
(0.688 mA/cm
2
) and the photocurrent density of S2-A sample reaches
0.652 mA/cm
2
at 1.23 V vs. RHE. In this work, the ion implantation combined with post
annealing method is found to be a valid method to improve the photoelectrochemical
performance, and it also can be further used to modify the other semiconductor photo-
electrodes materials.
© 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
* Corresponding author.
E-mail address: fren@whu.edu.cn (F. Ren).
Available online at www.sciencedirect.com
ScienceDirect
journal homepage: www.elsevier.com/locate/he
international journal of hydrogen energy xxx (xxxx) xxx
https://doi.org/10.1016/j.ijhydene.2020.01.178
0360-3199/© 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Please cite this article as: Wu H et al., Enhanced photoelectrochemical performance of an a-Fe
2
O
3
nanorods photoanode with embedded
nanocavities formed by helium ions implantation, International Journal of Hydrogen Energy, https://doi.org/10.1016/
j.ijhydene.2020.01.178