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Plasmonic Bi nanoparticle decorated BiVO
4
/rGO as
an efficient photoanode for photoelectrochemical
water splitting
Palyam Subramanyam
a
, Tanmoy Khan
a
, Gudipati Neeraja Sinha
a
,
Duvvuri Suryakala
b
, Challapalli Subrahmanyam
a,*
a
Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, 502285, Sangareddy, Telangana, India
b
Department of Chemistry, GITAM University, Visakhapatnam, India
highlights graphical abstract
Synthesized BiNPs decorated
BiVO
4
/rGO photoanode for PEC
water splitting.
The chemical stability and plas-
monic behavior of BiNPs improved
by rGO surface.
BieBiVO
4
/rGO yielded current
density of 6.05 mA/cm
2
with STH
efficiency of 2.34%.
High IPCE value of about 41% at
310 nm is achieved for the syn-
thesized photoanode.
article info
Article history:
Received 9 June 2019
Received in revised form
8 August 2019
Accepted 21 August 2019
Available online xxx
Keywords:
Photoelectrochemical cell
Water splitting
Bismuth nanoparticles
Reduced graphene oxide
Surface plasmon resonance
Charge transportation
abstract
We report the application of plasmonic Bi nanoparticles supported rGO/BiVO
4
anode for
photoelectrochemical (PEC) water splitting. Nearly, 2.5 times higher activity was observed
for Bi-rGO/BiVO
4
composite than pristine BiVO
4
. Typical results indicated that Bi-rGO/
BiVO
4
exhibits the highest current density of 6.05 mA/cm
2
at 1.23 V, whereas BieBiVO
4
showed the current density of only 3.56 mA/cm
2
. This enhancement in PEC activity on
introduction of Bi-rGO is due to the surface plasmonic behavior of BiNPs, which improves
the absorption of radiation thereby reduces the charge recombination. Further, the com-
posite electrode showed good solar to hydrogen conversion efficiency, appreciable incident
photon-to-current efficiency and low charge transfer resistance. Hence, Bi-rGO/BiVO
4
provides an opportunity to realize PEC water splitting.
©2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
*Corresponding author..
E-mail address: csubbu@iith.ac.in (C. Subrahmanyam).
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.2019.08.214
0360-3199/©2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Please cite this article as: Subramanyam P et al., Plasmonic Bi nanoparticle decorated BiVO
4
/rGO as an efficient photoanode for pho-
toelectrochemical water splitting, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2019.08.214
Introduction
Semiconductor based photoelectrochemical cells have been
receiving great attention for water splitting due to their ability
to absorb photons and generate voltage [1]. Alongside, the
efficiency of photoelectrochemical (PEC) cells strongly depend
on the generation of charge carriers, and their separation and
mobility [2]. In order to display high PEC activity, the genera-
tion of charge carriers must be high and their recombination
must be minimal [3]. The monoclinic-BiVO
4
is one such visible
light active photoanodes for water oxidation whose bandgap
lies between 2.4 and 2.5 eV, with suitably positioned valence
band edge for oxygen evolution [4e6] and its superior chem-
ical stability under light illumination [7]. Unfortunately, the
reported conversion efficiencies are poor due to its low carrier
mobility and fast recombination. To improve the mobility and
minimize the recombination, BiVO
4
has been modified by
various techniques such as formation of heterojunction with
other semiconductors [8,9], metal doping [10,11], loading co-
catalyst [12] etc. For example, in heterojunction systems like
TiO
2
/BiVO
4
[8] and WO
3
/BiVO
4
[9] excellent PEC activity are
reported. Metal doping such as Mo, W [10,11] is known to
enhance the charge carrier concentration and electronic
conductivity of BiVO
4
. Furthermore, introduction of a co-
catalyst on BiVO
4
also lead to significant improvement in
PEC water oxidation due to its enhanced photostability [12].
Among the numerous modification methods, introduction
of plasmonic metal nanoparticles gained sufficient attention
owing to their ability to improve the visible-light absorption and
prevent charge recombination due to the surface plasmon
resonance (SPR) effect [13]. As a result, good photochemical
energy conversion efficiency, photostability and interfacial
charge transfer kinetics are observed [14]. Noble metals like Au
[15,16] and Ag [14] have displayed surface plasmon resonance
(SPR) property when combined with semiconductors [17].For
example, Jeong et al. fabricated BiVO
4
electrode decorated with
Ag nanoparticles that showed ~3.3 times higher current than
BiVO
4
film [18]. Kim et al. reported Au/BiVO
4
/ZnO hetero-
junction to obtain ~4.5 times higher photocurrent than pristine
BiVO
4
photoelectrode [19]. Interestingly, bismuth nanoparticles
(BiNPs) exhibit unique electronic properties such as SPR, high
electron mean free path [20], high anisotropic fermi surface and
small bandgap energy, etc [21,22]. Moreover, optical response of
Bi nanostructures can be tuned between UV to IR region
[23e26]. Toudert et al. reported that BiNPs exhibit tunable SPR
phenomenon in near-UV to near-IR range region [27].The
heterojunction of Bi and BiVO
4
as reported by Wulan et al.
shows two-fold increment in photocurrent density (1.96 mA/
cm
2
at 1.23 V vs RHE) [28]. However, BiNPs have low chemical
stability and poor SPR property. In order to showcase its SPR
property, a support system is needed. With this background, we
have used rGO as the support to improve charge transfer from
BiNPs and thereby improving the overall PEC activity [14,29,30].
We fabricated Bi-rGO/BiVO
4
photoanode, where BiNPs
were synthesized by chemical reduction method while rGO by
Hummer’s method. The fabrication of photoelectrodes was
done by drop-casting. A systematic study was carried out to
propose and understand the role of Bi-nanoparticles and rGO
in improving the PEC performance of BiVO
4
.
Experimental section
Materials
Bismuth acetate (Bi(CH
3
COO)
3
), bismuth nitrate trihydrate
(Bi(NO
3
)
3
$3H
2
O), acetic acid (CH
3
COOH), sodium borohydride
(NaBH
4
), ethanol (C
2
H
5
OH), concentrated sulphuric acid
(H
2
SO
4
), graphite powder, sodium nitrate (NaNO
3
), potassium
permanganate (KMnO
4
), hydrogen peroxide (H
2
O
2
), acetyla-
cetone, vanadyl acetylacetonate, hydrochloric acid (HCl). FTO
glass used for fabrication of electrode has a sheet resistance of
13 U/cm
2
and is purchased from Aldrich. All the FTO glass
plates are pre-cleaned with HCl solution (35%), followed by DI
water and acetone.
Synthesis of BiNPs
The synthesis of BiNPs was carried out by chemical reduction
method. Briefly, ~193 mg of bismuth acetate was taken in
10 ml acetic acid, sonicated for 10 min to obtain a clear solu-
tion. To this solution, sodium borohydride was added drop-
wise under stirring. A brownish-black precipitate formed was
washed with deionized water followed by ethanol via centri-
fugation. The obtained precipitate was dried at 60 C.
Fabrication of BiVO
4
and BieBiVO
4
photoanodes
Firstly, BiVO
4
photoanode was prepared by organic decom-
position method followed by drop casting. The photoanode
was fabricated as follows:173 mg of Bi(NO
3
)
3
$5H
2
O was dis-
solved in glacial acetic acid (0.4 ml) and sonicated to form a
clear solution A. On the other hand, 95 mg of vanadyl acety-
lacetonate was taken in 4.6 ml of acetylacetone solution,
sonicated for 5 min and labelled as solution B. Solution A was
transferred to solution B and sonicated for 15 min, to obtain
BiVO
4
solution. For fabrication of BiVO
4
photoanode, 0.5 ml of
the as prepared solution was drop casted on FTO and
annealed at 500 C for 30 min. A yellow film of BiVO
4
was
formed. BieBiVO
4
was fabricated by dissolving BiNPs in
ethanol, sonication for 30 min, followed by drop-casting 0.5 ml
onto BiVO
4
electrode and dried at 70 C for 30 min.
Synthesis of Bi-rGO and Bi-rGO/BiVO
4
photoanodes
GO and rGO were prepared by modified Hummer’s method
(provided in SI). The prepared BiNPs and GO are dissolved in
ethanol and sonicated for 30 min. The resulting solution
contains BiNPs decorated on the surface of rGO.
The Bi-rGO/BiVO
4
electrode was fabricated by drop-casting
Bi-rGO (0.5 ml) solution on BiVO
4
electrode and dried at 70 C
for 30 min. The deposition scheme of Bi-rGO/BiVO
4
photo-
anode as presented in Scheme 1.
Characterizations
Shimadzu UV-3600 instrument was used for collecting
UVeVis spectra for synthesized photoanodes, whereas the
phase purity and presence of constituent materials was
confirmed by powder X-ray diffraction (XRD) recorded by
international journal of hydrogen energy xxx (xxxx) xxx2
Please cite this article as: Subramanyam P et al., Plasmonic Bi nanoparticle decorated BiVO
4
/rGO as an efficient photoanode for pho-
toelectrochemical water splitting, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2019.08.214
using a PANalytical XpertPRO diffractometer. Surface mor-
phologies of the samples were measured using a FESEM (Zeiss
supra 40), whereas, TECNAI G-2 FEI (300 kV) was used to collect
HR-TEM images.
Photoelectrochemical measurements
Linear sweep voltammetric (IeV) studies were performed on
LOT-Oriel with a 150 W Xe with a power density of
~100 mW cm
2
, which is measured by Newport Oriel instru-
ment (Optical power/Energy meter-model 842.PE). Chro-
noamperometric (I-t) studies, electrochemical impedance
spectroscopic (EIS) and cyclic voltammograms (CV) studies
were performed on an Autolab PGSTAT 302 N using NOVA 2.1
software. Incident photon-to-current conversion efficiency
(IPCE) data was performed by Oriel IQE-200 instrument with a
250 W quartz tungsten halogen lamp as a light source. A
Trace-1310 GC equipped with a TCD was used to quantify
hydrogen gas. The PEC measurements consist of a three
electrode system, where the fabricated electrodes act as the
working electrode (WE), Ag/AgCl, platinum (Pt) wire as the
reference electrode (RE) and the counter electrode (CE)
respectively. The fabricated electrodes were tested in 0.1 M
Na
2
SO
4
solution.
Results and discussion
The formation of BiVO
4
, BiNPs and GO was confirmed by
XRD patterns as displayed in Fig. 1a. As noticed in Fig. 1a,
BiVO
4
has monoclinic crystal lattice with (110), (121), (040),
(200), (002), (112) and (051) crystal planes (JCPDS NO-140688)
at 2qvalues ¼19.1, 28.91, 30.05, 34.79, 35.42, 40.07 and 42.6
respectively. BiNPs have rhombohedral crystal lattice with
(003), (012), (104), (110), (015), (006), (202), (024), (116) and
(122) planes (JCPDS NO-851331). For GO, a characteristic
(002) plane of graphene oxide was confirmed from the peak
at 2q¼10.28while, the Bi-rGO showed similar peaks as
BiNPs, however, no rGO peak due to its low concentration
(Fig. S1). Raman spectral analysis of synthesized samples
BiNPs, Bi-rGO and Bi-rGO/BiVO
4
are displayed in Fig. 1b,
which shows two characteristic vibrational bands at 68 and
96 cm
1
corresponding to E
g
and A
1g
modes for BiNPs [31].
For Bi-rGO, the two additional peaks at 1338 and 1583 cm
1
are due to the defect (D-band) and graphitic (G-band) of
rGO respectively. This confirms that BiNPs are incorporated
on the rGO sheets. Pure BiVO
4
and BieBiVO
4
showed
similar Raman bands at 216, 375 and 825 cm
1
which are
due to asymmetric and symmetric bending vibrational
bands and symmetric stretching vibration of VO
4
3
,
respectively (Fig. S2). For Bi-rGO/BiVO
4
composite, extra
peaks at 68, 1315 and 1553 cm
1
are associated with the
BiNPs, defect (D-band) and graphitic (G-band) bands of rGO
respectively.
The absorption spectra of BiNPs, Bi-rGO, BiVO
4
,BieBiVO
4
and Bi-rGO/BiVO
4
composites are shown in Fig. 2. The Bi
nanoparticles displayed a sharp surface plasmon resonance
peak centered at 320 nm that extended to near IR region.
Further, BiNPs supported on rGO show improvement in the
absorption intensity as shown in Fig. 2b, where absorption
peaks are observed at 280 and 320 nm for rGO and SPR effect of
BiNPs respectively. The absorption spectra of BiVO
4
reveal
that they exhibit a narrow absorption with an absorption edge
at 580 nm corresponding to the bandgap of 2.15 eV. BiNPs in
combination with BiVO
4
lead to enhanced absorption. The
absorption for BieBiVO
4
and Bi-rGO/BiVO
4
composites are
shown in Fig. 2d.
The morphology of the samples was analyzed by FE-SEM
and are displayed in Fig. 3. The synthesized Bi nanoparticles
have a flower like morphology (Fig. 3a), whereas, rGO has a
sheet like morphology (Fig. 3b). The surface morphologies of
BiVO
4
appear to be porous with an average diameter of
300e350 nm as shown in Fig. 3c. Fig. 3d indicates the presence
of BiNPs on BiVO
4
. The composite Bi-rGO/BiVO
4
shows similar
morphology like BieBiVO
4
and randomly aggregated with no
specific shape but high surface roughness. The morphology of
the composite is shown in Fig. 3e and the EDAX shown in
Fig. 3f reveals the presence of BiNPs and the relative atomic
percentages.
The HR-TEM images of BiNPs, Bi-rGO and Bi-rGO/BiVO
4
composite are shown in Fig. 4. The high resolution image of Bi-
rGO and the composite are shown (Fig. 4b and d). The lattice
spacing of 0.24 nm of BiNPs matches with the d-spacing
calculated from (012) plane in XRD (JCPDS-851331) (Fig. 4a and
c). Similarly, the lattice spacing of 0.31 nm matches with (121)
plane for monoclinic BiVO
4
(JCPDS NO-140688) (Fig. 4e). SAED
pattern of Bi-rGO/BiVO
4
composite is shown in Fig. 4f along
with the planes.
Scheme 1 eThe deposition scheme of Bi-rGO/BiVO
4
photoanode.
international journal of hydrogen energy xxx (xxxx) xxx 3
Please cite this article as: Subramanyam P et al., Plasmonic Bi nanoparticle decorated BiVO
4
/rGO as an efficient photoanode for pho-
toelectrochemical water splitting, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2019.08.214
Fig. 1 e(a) X-ray diffraction patterns of pristine BiVO
4
, BiNPs and GO films (b) Raman spectra of BiNPs, Bi-rGO and Bi-rGO/
BiVO
4
nanocomposite.
Fig. 2 eAbsorption spectra of (a) BiNPs (b) Bi-rGO (c) pristine BiVO
4
and (d) BieBiVO
4
and Bi-rGO/BiVO
4
nanocomposite.
international journal of hydrogen energy xxx (xxxx) xxx4
Please cite this article as: Subramanyam P et al., Plasmonic Bi nanoparticle decorated BiVO
4
/rGO as an efficient photoanode for pho-
toelectrochemical water splitting, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2019.08.214
Photoelectrochemical studies
The PEC studies were performed under visible light illumina-
tion. The LSV plots or current versus potential (I vs V) curves
are displayed in Fig. 5a. The electrolyte used for the experi-
ment is 0.1 M of Na
2
SO
4
. The potential was measured with
respect to Ag/AgCl reference electrode and converted to RHE
as shown in supporting information (SI). All the studied pho-
toelectrodes show no photocurrent under dark conditions.
Upon light on and off mode (chopped illumination), the
observed photocurrent density for BiVO
4
,BieBiVO
4
and Bi-
rGO/BiVO
4
nanocomposite is 2.39, 3.56 and 6.05 mA/cm
2
at
1.23 V, respectively. Bi-rGO/BiVO
4
composite produced the
highest photocurrent density, which is two-times and
nearly three-times higher than BieBiVO
4
and BiVO
4
,
respectively. The Bi-rGO/BiVO
4
has the onset potential of
0.15 V, which is lower than pristine BiVO
4
(0.26 V). The
decrease in the onset potential for Bi-rGO/BiVO
4
can be due
to increase in charge carrier separation and facile transfer
due to incorporation of Bi and rGO. Among BieBiVO
4
and
Bi-rGO/BiVO
4
, the latter has higher photocurrent density
due to conductive nature of rGO. Solar-to-hydrogen con-
version (STH) for BiVO
4
,BieBiVO
4
and Bi-rGO/BiVO
4
nano-
composite has been calculated by using equation (2) (SI),
which are 0.82, 1.35 and 2.34% at 0.61 V respectively
(Fig. 5b). This improved activity of Bi-rGO/BiVO
4
suggests
that rGO stabilize BiNPs and improves the activity. The HER
isshowninphotograph(Fig. S3), which demonstrates
Fig. 3 eFE-SEM images of (a) BiNPs (b) Bi-rGO (c) pristine BiVO
4
(d) BieBiVO
4
(e) Bi-rGO/BiVO
4
composite and (f) EDAX images
of Bi-rGO/BiVO
4
composite.
international journal of hydrogen energy xxx (xxxx) xxx 5
Please cite this article as: Subramanyam P et al., Plasmonic Bi nanoparticle decorated BiVO
4
/rGO as an efficient photoanode for pho-
toelectrochemical water splitting, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2019.08.214
evolution of H
2
bubbles at the Pt CE during the PEC
measurement.
The stability of the photoanodes is examined by chro-
noamperometric studies. The photocurrent for BiVO
4
,
BieBiVO
4
and Bi-rGO/BiVO
4
electrodes at 0.6 V vs RHE as a
function of time is shown in Fig. 6a. It is worth mentioning
that Bi-rGO/BiVO
4
nanocomposite exhibits long term stability
up to 5000 s. The current density value obtained in LSV and
chronoamperometry is consistent and in both studies, Bi-rGO/
BiVO
4
composite showed higher current than pristine BiVO
4
and BieBiVO
4
. The H
2
evolution, quantified by gas chroma-
tography is plotted as a function of time. As shown in Fig. 6b,
the Bi-rGO/BiVO
4
photoanode showed the maximum H
2
evo-
lution of 2466 mmol at 2 h as compared to BiVO
4
(1071 mmol)
and BieBiVO
4
(1941 mmol). Impressively, the composite
exhibited nearly 2.5 times increment in H
2
evolution than pure
BiVO
4
electrode. Thus, the quantification studies feature that
Bi-rGO/BiVO
4
is a promising photoanode for PEC water split-
ting. The IPCE response of the all photoelectrodes is shown in
Fig. 6c, BieBiVO
4
and Bi-rGO/BiVO
4
exhibit 34 and 41% con-
version, respectively at 310 nm as compared to only 27% for
pure BiVO
4
. The IPCE expression is given in SI. The best per-
formance is shown by Bi-rGO/BiVO
4
due to the formation of
energetic hot electrons by plasmonic excitation of BiNPs. This
Fig. 4 eHR-TEM images of (a) BiNPs, (b) and (c) are Bi-rGO, (d) and (e) are Bi-rGO/BiVO
4
composite, (f) SAED pattern of Bi-rGO/
BiVO
4
composite.
Fig. 5 e(a) LSV plots and (b) STH efficiency of bare BiVO
4
,BieBiVO
4
and Bi-rGO/BiVO
4
nanocomposite photoelectrodes under
solar radiation.
international journal of hydrogen energy xxx (xxxx) xxx6
Please cite this article as: Subramanyam P et al., Plasmonic Bi nanoparticle decorated BiVO
4
/rGO as an efficient photoanode for pho-
toelectrochemical water splitting, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2019.08.214
is also supported by the maximum photocurrent at around
310 nm. Impressively, the composite exhibited higher IPCE
than other electrodes. This concludes that BiNPs on rGO
suppresses the charge recombination and also facilitates
higher charge injection transfer to the composite. BiNPs
chemical stability and plasmon-induced hot electrons injec-
tion are complemented by the conductive nature of rGO. In
addition, the high surface area and electrical conductivity of
rGO improves the interfacial active sites in BiVO
4
which were
unavailable in pure BiVO
4
thereby improving the dynamics of
BiVO
4
for OER reaction.
In order to validate the ease of charge transfer at the
electrode-electrolyte interface, EIS experiments were per-
formed. The Nyquist plots obtained for BiVO
4
,BieBiVO
4
and Bi-
rGO/BiVO
4
photoanodes over the frequency range (1 kHz-1 Hz)
under light irradiation are shown in Fig. 6d. All the electrodes
have a solution resistance ~41 U.HighR
ct
value of 1.46 kUfor
BiVO
4
is due to low charge separation and weak carrier mobility
which are the main reasons for its poor water oxidation per-
formance. However, BiNPs loading on the surface of BiVO
4
enhanced the charge carrier density since BiNPs acts as active
sites for the PEC reaction which is evident from the R
ct
value of
0.80 kUas shown in Fig. 6d. Further,the rGO supported BiNPs on
BiVO
4
significantly lower charge resistance (R
ct
value of 0.61 kU)
which is attributed to the nature of rGO acting as a medium of
transportation. In typical, the diameter of the semicircle rep-
resents charge transfer resistance (R
ct
)intheNyquistplot.
Lower the R
ct,
better the charge transfer process at the
electrode-electrolyte interface [32e34].LowestR
ct
is observed
for Bi-rGO/BiVO
4
composite over the fabricated photoanodes
(BiVO
4
and BieBiVO
4
). In simple terms, it could be explained as
photogenerated electrons from BiVO
4
can be effectively
collected with the help of Bi-rGO and consolidated electronsare
transferred to counter electrode. Therefore, Bi-rGO/BiVO
4
exhibit dominated PEC response.
The mechanistic details of the electron transfer process in
Bi-rGO/BiVO
4
composite photoelectrodes are shown in the
schematic representation in Fig. 7c. The Fermi level of BiNPs,
VB and CB positions of BiVO
4
are obtained from cyclic vol-
tammetry (Fig. 7a and b). The procedure for calculation of
band positions in the energy level diagram is presented in (SI).
Due to absorption of solar radiation, excitons are generated.
The surface plasmons are facilitated by BiNPs and electrons
from Bi-rGO are injected into the CB of BiVO
4
. Since, Bi-rGO
facilitates quick charge injection, the generated charge car-
riers are efficiently transferred to FTO. Therefore, the pres-
ence of rGO accelerates the overall charge transport and
hence better electron injection and enhanced PEC activity.
Fig. 6 e(a) Stability of pure BiVO
4
,BieBiVO
4
and Bi-rGO/BiVO
4
nanocomposite photoelectrodes at 1.23 V vs RHE during
5000 s. (b) H
2
evolution of Bi-rGO/BiVO
4
under light illumination under 2 h in comparison with pure BiVO
4
and BieBiVO
4
. (c)
IPCE of pristine BiVO
4
,BieBiVO
4
and Bi-rGO/BiVO
4
photoelectrodes under monochromatic light radiation. (d) Nyquist plots
for BiVO
4
,BieBiVO
4
and Bi-rGO/BiVO
4
photoelectrodes.
international journal of hydrogen energy xxx (xxxx) xxx 7
Please cite this article as: Subramanyam P et al., Plasmonic Bi nanoparticle decorated BiVO
4
/rGO as an efficient photoanode for pho-
toelectrochemical water splitting, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2019.08.214
Briefly, the PEC activity could be explained by the light-driven
holes in the VB of BiVO
4
that react with electrolyte to evolve
oxygen and release protons. On the other side, the electrons
are transferred through external circuit to counter electrode
which favor HER. The whole movement of photogenerated
carriers effectively takes place due to the conducting nature of
Bi-rGO, which improves the charge transfer thereby
improving the over all PEC performance for hydrogen
production.
Conclusions
A promising photoanode Bi-rGO/BiVO
4
was fabricated and
used for photoelectrochemical water splitting reaction. This
ternary photoanode displayed the best photocurrent density
of 6.05 mA/cm
2
at 1.23 V over BiVO
4
and BieBiVO
4
with STH
efficiency of 2.34% at 0.61 V. The best IPCE and less charge
transfer resistance for Bi-rGO/BiVO
4
facilitates the charge
separation and improves the charge carrier mobility. Chro-
noamperometric results revealed the stability of the photo-
anode over 5000 s. The SPR property of BiNPs is enhanced by
rGO and efficient PEC activity of Bi-rGO/BiVO
4
is due to com-
bined action of BiNPs in improving the charge carrier density
and rGO in increasing the charge carrier mobility.
Acknowledgements
PS thanks CSIR for a senior research fellowship. G.N.S thanks
DST-Inspire (Reg No. IF170949), New Delhi, India for the award
of research fellowship.
Appendix A. Supplementary data
Supplementary data to this article can be found online at
https://doi.org/10.1016/j.ijhydene.2019.08.214.
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Please cite this article as: Subramanyam P et al., Plasmonic Bi nanoparticle decorated BiVO
4
/rGO as an efficient photoanode for pho-
toelectrochemical water splitting, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2019.08.214
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international journal of hydrogen energy xxx (xxxx) xxx 9
Please cite this article as: Subramanyam P et al., Plasmonic Bi nanoparticle decorated BiVO
4
/rGO as an efficient photoanode for pho-
toelectrochemical water splitting, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2019.08.214
