Journal of Catalysis
In situ grown heterojunction of Bi WO /BiOCl for efficient
2
6
photoelectrocatalytic CO reduction
2
a
a
a
a
b
a,b,
⇑
Jixian Wang , Yan Wei , Bingjie Yang , Bing Wang , Jiazang Chen , Huanwang Jing
a
State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, Gansu, China
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, Shanxi, China
b
a r t i c l e i n f o
a b s t r a c t
Article history:
CO2 reduction is a very attractive research field in environmental, material, and chemical science in light
Received 23 April 2019
Revised 3 June 2019
Accepted 4 June 2019
of the energy crisis and the greenhouse effect. In this study, Bi
2 6
WO /BiOCl heterojunctions were fabri-
cated onto the F-SnO transparent conductive glass in situ by a hydrothermal method. These new photo-
2
cathodes, named BCW-X, were characterized by such methods as scanning electron microscopy,
transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscope, and UV-vis spec-
tra. Their morphology is a good 2D layered/3D flower structure. The exposed crystal plane of BiOCl was
changed from (1 0 1) of the pristine form to (1 1 2) in the heterojunction. The photoelectrocatalytic
Keywords:
CO reduction
2
Heterojunction
Photoelectrocatalysis
Charge separation efficiency
reduction of CO
2
was carried out in BCW-X|KHCO
3
|BiVO
4
under irradiation by an Xe lamp and external
|BiVO produces ethanol at a rate
) with 80.0% selectivity under ꢀ1.0 V. The apparent quantum effi-
ciency is up to 0.63%, about three times that of composite BiOCl–Bi WO as photocathode. These phe-
voltage from a Si solar cell (ꢀ0.6 to ꢀ1.1 V). A PEC cell of BCW-6|KHCO
3
4
ꢀ
1
ꢀ2
ꢀ1 ꢀ1
of 11.4
l
M h cm (600
l
mol h
g
2
6
nomena can be attributed to the better photogenic electron–hole separation and high charge
separation efficiency of heterojunctions.
Ó 2019 Elsevier Inc. All rights reserved.
1
. Introduction
2 2 3
Semiconductors such as TiO [13], CdS [14], Ga O [15], ZnO
[
16], Si [17], and g-C [18] have been used as catalysts in CO
3
N
4
2
Along with fast development of human society, the total con-
reduction. Recently, much attention has been paid to Bi-based
semiconductors in photocatalysis [19–23]. 2D layered semicon-
ductors of bismuth oxyhalides (BiOX, X = Cl, Br, and I) have been
applied to the degradation of hazardous pollutants [24], water
sumption of fossil fuels has been climbing to an unbelievable level,
resulting in climate change and environment issues [1]. Therefore,
it is of great significance to harvest and store solar energy [2] in
chemical fuels by using abundant CO
2
2
and H O via photocatalysis
2
splitting [25], and CO conversion [26,27]. However, the wide band
[
3–5] and electrocatalysis [6–8]. Apart from the photocatalytic
gaps of BiOX preclude their application under visible light [28]. Dif-
ferent strategies have been developed to overcome this drawback
[29], including hierarchical nanostructures [30] and crystal-facet
control [31]. On the other hand, various composites with
heterostructures were constructed from BiOCl and other materials
to augment their catalytic activity, such as graphene [32], metal
oxides [33], metals [34,35], and salts [36].
As is well known, semiconductor heterojunctions can enhance
the light absorption, the separation efficiency of electrons and
holes, and the lifetime of photogenic carriers in hybrid materials
2
and electrocatalytic reduction of CO , photoelectrocatalytic (PEC)
CO
of CO
2
reduction [9–11] is also a promising method for the reduction
into fuels and chemicals. PEC CO reduction can integrate
2
2
and optimize the advantages of photocatalysis and electrocatalysis
to enhance their efficiency. The energetic photoelectrons could
overcome the high overpotential of the electrochemical process
and electrons from the circuit could prohibit the combination of
photoelectrons and holes. To accelerate the sluggish kinetics of
multielectron reactions, some co-catalysts, such as Au, Ag, Pt, Pd,
Ru, Rh, Ir, and Re [12], were deposited on the surfaces of
semiconductors.
[37]. The Zeng group has designed a TiO
enhances the separation efficiency of photogenic charges [38].
The Yu group has built a 2D/2D heterojunction of Ti /Bi WO
to improve photocatalytic CO reduction [39]. Our group has
reported Ti /TiO [40], g-C /Ti [41], and TiO /ZnO [42]
2
/GaP p–n junction that
3
C
2
2
6
2
⇑
Corresponding author at: State Key Laboratory of Applied Organic Chemistry,
College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou
7
C
3 2
2
3
N
4
3
C
2
2
heterojunctions, showing evident improvements in PEC CO
reduction in water.
2
021-9517/Ó 2019 Elsevier Inc. All rights reserved.
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