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Article
Engineering NiS/Ni2P Heterostructures for
Efficient Electrocatalytic Water Splitting
Xin Xiao, Dekang Huang, Yong Qing Richard Fu, Ming Wen, Xingxing Jiang, Xiaowei
Lv, Man Li, Lin Gao, Shuangshuang Liu, Mingkui Wang, Chuan Zhao, and Yan Shen
ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.7b16430 • Publication Date (Web): 15 Jan 2018
Downloaded from http://pubs.acs.org on January 22, 2018
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1
Engineering NiS/Ni
2
P Heterostructures for
Efficient Electrocatalytic Water Splitting
Xin Xiao,
†
Dekang Huang,
‡
Yong Qing Fu,
┴
Ming Wen,
§
Xingxing Jiang,
†
Xiaowei Lv,
†
Man Li,
†
Lin Gao,
†
Shuangshuang Liu,
†
Mingkui Wang,
†
Chuan Zhao,
#
Yan Shen*
,†
†
Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and
Technology, Wuhan 430074, P. R. China
‡
College of Science, Huazhong Agricultural University, Wuhan 430070, P. R. China
┴
Faculty of Engineering and Environment, Northumbria University, Newcastle Upon Tyne, NE1
8ST, UK
§
School of Chemistry Science and Engineering, Tongji University, Shanghai 200092, P. R. China
#
School of Chemistry, The University of New South Wales, Sydney, NSW, 2052, Australia
KEYWORDS: Bifunctional electrocatalyst, heterostructures, nickel phosphide, nickel sulfide,
overall water splitting
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ABSTRACT
Developing high-active and low-cost bifunctional materials for catalyzing hydrogen evolution
reaction (HER) and oxygen evolution reaction (OER) holds pivotal role in water splitting.
Therefore, we present a new strategy to form NiS/Ni
2
P heterostructures. The as-obtained
NiS/Ni
2
P/CC requires overpotentials of 111 mV for the HER and 265 mV for the OER to reach a
current density of 20 mA cm
-2
, outperforming their counterparts such as NiS and Ni
2
P under the
same conditions. Additionally, the NiS/Ni
2
P/CC electrode requires a 1.67 V cell voltage to deliver
10 mA cm
-2
in two-electrode electrolysis system, which is comparable to the cell using the
benchmark Pt/C||RuO
2
electrode. Detailed characterizations reveal that strong electronic
interactions between NiS and Ni
2
P, abundant active sites, and smaller charge transfer resistance
contribute to the improved HER and OER activity.
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1. INTRODUCTION
The development of renewable fuels to replace traditional fossil fuels is highly demanded for
addressing the increasingly serious energy and environmental issues facing the society.
1
Hydrogen
generated from water splitting provides a very promising strategy for the above-mentioned issues
because hydrogen can act as an energy carrier and the combustion product is only water.
2
However,
the hydrogen production via water splitting faces the problem of high energy consumption
associated with the high electrolysis potential.
3
RuO
2
and Pt-based materials are commonly
considered to be the best electrocatalysts for oxygen evolution reaction (OER) and hydrogen
evolution reaction (HER), respectively.
4-7
However, the scarcity of these precious metal
electrocatalysts inevitably hinders their large-scale applications.
Over the past few decades, separated non-noble metal catalysts that are optimized for HER and
OER have emerged as novel materials for catalyzing water splitting, such as transition metal
nitrides
8,9
, carbides
10,11
and sulfides
12
for HER, perovskite oxides,
13,14
transition metal oxides
15,16
and hydroxides
17,18
for OER, which are quite prospective to replace precious metal catalysts in
large-scale applications. However, developing efficient and durable bifunctional electrocatalysts
toward both HER and OER in the same electrolytes with advantages in terms of not only
simplifying system and reducing costs, but also providing high efficiency are quite challenge.
19-21
Recently, earth-abundant transition metal compounds have been corroborated to show decent
electrochemical activity and exhibit high durability for both HER and OER, which is quite suitable
for their application in water splitting.
22-23
In spite of this, the activity of those reported bifunctional
catalysts for catalyzing water splitting reaction are still inferior to that of Pt||RuO
2
couple.
Therefore, much efforts have been paid to promote catalytic performance of electrocatalysts over
the past few decades.
24-28
Various strategies have been employed to rationally design catalysts,
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