Gold-Nanoparticle-Loaded Carbonate-Modified Titanium(IV) Oxide Surface: Visible-Light-Driven Formation of Hydrogen Peroxide from Oxygen

Article abstract of DOI:10.1002/anie.201606734

Gold nanoparticle-loaded rutile TiO₂with a bimodal size distribution around 10.6 nm and 2.3 nm (BM-Au/TiO₂) was prepared by the deposition precipitation and chemical reduction (DP-CR) technique. Visible-light irradiation (λ>430 nm) of the BM-Au/TiO₂plasmonic photocatalyst yields 35 μm H₂O₂in aerated pure water at irradiation time (t_p)=1 h, and the H₂O₂concentration increases to 640±60 μm by the addition of 4 % HCOOH as a sacrificing electron donor. Further, a carbonate-modified surface BM-Au/TiO₂(BM-Au/TiO₂-CO₃^2?) generates a millimolar level of H₂O₂at t_p=1 h with a quantum efficiency (Φ) of 5.4 % at λ=530 nm under the same conditions. The recycle experiments confirmed the stable performance of BM-Au/TiO₂.

Full text of DOI:10.1002/anie.201606734

Angewandte
Communications
Chemie
International Edition: DOI: 10.1002/anie.201606734
German Edition: DOI: 10.1002/ange.201606734
Plasmonic Photocatalysis
Gold-Nanoparticle-Loaded Carbonate-Modified Titanium(IV) Oxide
Surface: Visible-Light-Driven Formation of Hydrogen Peroxide from
Oxygen
Miwako Teranishi, Riyoko Hoshino, Shin-ichi Naya, and Hiroaki Tada*
Abstract: Gold nanoparticle-loaded rutile TiO with a bimodal
from 500 nm to 650 nm is desirable as an energy source
[Eq. (1)].
2
size distribution around 10.6 nm and 2.3 nm (BM-Au/TiO2)
was prepared by the deposition precipitation and chemical
reduction (DP-CR) technique. Visible-light irradiation (l >
0
ꢁ1
1
=2 O þ H O ! H O
D G ¼ þ116:8 kJ mol
ð1Þ
2
2
2
2
r
4
3
30 nm) of the BM-Au/TiO plasmonic photocatalyst yields
2
5 mm H O in aerated pure water at irradiation time (t ) = 1 h,
UV-light irradiation of TiO
2
in water yields H
2
O
2
, but the
2
2
p
[
5]
and the H O concentration increases to 640 ꢀ 60 mm by the
H
2
O
2
concentration is only limited to micromolar levels. We
can be produced
by UV-light irradiation of gold nanoparticle (NP)-
2
2
addition of 4% HCOOH as a sacrificing electron donor.
have reported that a millimolar level of H
from O
loaded TiO
The photocatalytic synthesis of H
studied to increase its steady-state concentration by using
O
2 2
Further, a carbonate-modified surface BM-Au/TiO (BM-Au/
TiO -CO3 ) generates a millimolar level of H O at t = 1 h
with a quantum efficiency (F) of 5.4% at l = 530 nm under the
same conditions. The recycle experiments confirmed the stable
performance of BM-Au/TiO2.
2
2
2
ꢁ
[6]
(Au/TiO
) in an aqueous solution of ethanol.
has been intensively
2
2
2
p
2
2
O
2 2
[
7]
heterogeneous photocatalysts such as Au-Ag/TiO
,
gra-
A
2
[
8]
[9]
phene oxide-TiO2, and silicon nanowire-TiO -Au.
2
H
ydrogen peroxide (H O ) has attracted much interest as
coming challenge is to use the visible light as the energy
source for the effective sunlight utilization. So far, several
2
2
[
1]
not only a “green” oxidant for organic synthesis but also the
[
2]
source for a new fuel cell. Presently, most H O is produced
by the anthraquinone oxidation process through the many
steps needing large amounts of input energy and organic
solvent. As alternative, various chemical and physical
methods have recently been studied. If H O2 can be
reports on the H
photocatalysts including graphitic carbon nitride (g-C N
3 4
2
O
2
synthesis from O
2
using visible-light
)-
have been published. Particularly,
a high F value of about 10% has been achieved at l = 420 nm
2
2
[
10,11]
based photocatalysts
[
3]
[4]
[11]
in the g-C
N system; however, it is inactive at l > 500 nm.
3 4
2
produced from O and water, a sustainable energy cycle is
On the other hand, the plasmonic photocatalysts represented
2
[12]
completed by combining with the H O -based fuel cell
by Au/TiO
By using the Au/TiO
2
2
have appeared as a new class of photocatalysts.
2
2
(
Scheme 1). For this endergonic reaction to proceed, the
plasmonic photocatalyst, various
effective use of sunlight with a broad energy peak locating
oxidative transformations including alcohol to carbonyl
[
13,14]
[15]
[16]
compounds,
thiol to disulfide, benzene to phenol,
[17]
and amine to imine
have been developed. A bimodal
(
BM)-Au/TiO plasmonic photocatalyst has been shown to
2
have a potential for the application to the reductive trans-
[
18]
formation. So far, the BM-Au/TiO plasmonic photocata-
2
lyzed reaction is only limited to the reduction of nitrobenzene
analogs to the corresponding azobenzenes.
Herein we report the visible-light-driven reduction of O2
to H O2 in pure water by the BM-Au/TiO2 plasmonic
2
photocatalyst, further showing that carbonate-surface modi-
2
ꢁ
fied BM-Au/TiO (BM-Au/TiO -CO ) yields a millimolar
2
2
3
level of H O in the presence of formic acid (HCOOH). BM-
2
2
Scheme 1. Solar oxygen cycle using the H O -based fuel cell.
2
2
[18]
Au/TiO2 was prepared by the DP-CR technique.
The
visible-light activity of Au/TiO depends on the crystal form of
2
[14]
TiO , and rutile is superior to anatase in contrast to the UV-
2
[19]
[
*] M. Teranishi, Dr. S. Naya
Environmental Research Laboratory, Kindai University
-4-1, Kowakae, Higashi-Osaka, Osaka 577-8502 (Japan)
light activity of TiO for most photocatalytic reactions. At
2
the first step, large Au NPs were loaded on rutile TiO (L-Au/
2
3
[20]
ꢁ
TiO ) by the DP method. At the second step, [Au(OH) Cl]
2
3
R. Hoshino, Prof. Dr. H. Tada
Department of Applied Chemistry
School of Science and Engineering, Kindai University
complex ions were adsorbed on the TiO surface of L-Au/
2
TiO , and then, they were reduced by NaBH to yield small
2
4
Au NPs. For comparison, the second CR procedure was
3-4-1, Kowakae, Higashi-Osaka, Osaka 577-8502 (Japan)
E-mail: h-tada@apch.kindai.ac.jp
applied to unmodified TiO to produce small Au NP-loaded
2
TiO (S-Au/TiO ). The Au 4f X-ray photoelectron spectra of
Supporting information for this article can be found under:
http://dx.doi.org/10.1002/anie.201606734.
2
2
Au/TiO have two signals at 87.0 and 83.3 eV due to the
2
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1
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Communications
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2
ꢁ
emissions from the Au 4f 5/2 and Au 4f 7/2 orbitals for
TiO -CO3 . The larger Au loading amount is responsible for
2
[
21]
III
metallic Au, respectively.
adsorbed on TiO is reduced to metallic Au by NaBH at the
Evidently, the Au complex
the stronger absorption intensity.
We examined the photocatalytic activity of BM-Au/TiO2
for the O reduction reaction (ORR) to H O without and
2
4
second step.
2
2
2
Transmission electron microscopy (TEM) images (see
Figure S1 in the Supporting Information) and the Au particle
with sacrificing electron donors (4% C H OH or HCOOH),
2 5
2
ꢁ
and that of BM-Au/TiO -CO3 in the presence of 4%
2
size distribution for L-Au/TiO show that Au particles with
HCOOH. Catalyst was added in an aerated aqueous solution
(10 mL), and H O generated under irradiation of visible light
(l > 430 nm) at 298 K was quantified by the iodometric
2
a mean size (d) of 9.7 nm (standard deviation s = 1.6 nm) are
highly dispersed on the TiO surface. In BM-Au/TiO , l-and
2
2
2
2
S-Au particles with d values of 10.6 nm (s = 4.0 nm) and
.3 nm (s = 1.3 nm), respectively, are separately formed on
TiO . For S-Au/TiO , the d value was 2.3 nm (s = 1.0 nm). The
titration. To evaluate the activity at the comparable Au
2
amount, 20 mg of S- and L-Au/TiO was added in each run,
2
2
ꢁ
while 10 mg of BM-Au/TiO and BM-Au/TiO -CO
were
2
2
2
2
3
Au loading amounts were determined to be 0.52 wt% for S-
Au/TiO , 0.49 wt% for L-Au/TiO , and 0.88 wt% for BM-Au/
used. Figure 2A shows time courses for the H O generation
2
2
2
2
TiO by inductively coupled plasma spectroscopy.
2
2
ꢁ
Further, CO3 ions were adsorbed on the BM-Au/TiO2
surface from a 100 mm Na CO aqueous solution (BM-Au/
2
3
2
ꢁ
TiO -CO3 ). Figure 1A shows diffuse reflectance Fourier
2
Figure 2. A) Time courses for the BM-Au/TiO -phatocatalytized H O
2
2
2
generation in the absence (black) and presence of 4% C H OH
2
5
2
ꢁ
(
green) and 4% HCOOH (red), and for the BM-Au/TiO -CO -photo-
2 3
catalyzed H O generation with 4% HCOOH (purple) under irradiation
2
2
of visible light (l>430 nm, light intensity integrated from 420 to
ꢁ
2
4
85 nm=4.0 mWcm ) at 298 K. B) Photocatalytic activity of S-Au/
2
ꢁ
Figure 1. A) DRIFT spectra for CO3 ion-adsorbed BM-Au/TiO , and
2ꢁ
2
TiO , L-Au/TiO , BM-Au/TiO , and BM-Au/TiO -CO for the reduction
of O to H O in an aqueous solution containing 4% HCOOH
2 2 2
(pH 1.7) in the dark and under irradiation of visible light (l>430 nm,
light intensity integrated from 420 to 485 nm=4.0 mWcm ) at 298 K.
2
2
2
2
3
TiO for comparison. B) UV/Vis absorption spectra for the unmodified
TiO and Au/TiO samples and the solar spectrum.
2
2
2
ꢁ2
2
ꢁ
transform infrared (DRIFT) spectra for BM-Au/TiO -CO3
,
2
and TiO for comparison. In the spectrum of TiO , a signal
in the BM-Au/TiO system. No H O was generated in the
2
2
2
2
2
assignable to the stretching vibration of the surface Ti-OH
dark. Visible-light irradiation of BM-Au/TiO in pure water
2
ꢁ
1
groups [n(Ti -OH)] is observed at 3695 cm , while in the
yields 35 ꢀ 5 mm H O at t = 20 minutes. Since the Au/TiO
s
2
2
p
2
ꢁ1
1
200–1800 cm region, a signal due to the deformation
plasmonic photocatalyst oxidizes water under visible-light
ꢁ1
[23,24]
vibration of adsorbed water [d(H O)] is situated at 1637 cm .
The spectrum of BM-Au/TiO -CO3 has additional two
characteristic signals at 1520 and 1448 cm , which can be
irradiation,
the total reaction is expressed by Equa-
2
2
ꢁ
tion (1). The addition of the electron donors greatly enhances
2
ꢁ1
the reaction, and the H O2 concentration increases with
2
assigned to the antisymmetric [n (OCO)] and symmetric
increasing t . In the HCOOH-added system, the H O
2
a
p
2
2
ꢁ
[
ns(OCO)] stretching vibrations for the CO3 ions adsorbed
concentration reaches 640 ꢀ 60 mm at t = 1 h. We have
p
[
22]
on the TiO surface with a bidentate structure. Also, the
recently reported that a decreasing pH of the reaction
2
n(Ti -OH) signal significantly weakens with the adsorption of
solution accelerates the Au/TiO2 photocatalytic ORR to
s
2
ꢁ
2ꢁ
[25]
CO3 ions. Evidently, CO3 ions are adsorbed on the Ti -OH
H O under UV-light irradiation.
The pH values of the
s
2
2
2
ꢁ
sites of BM-Au/TiO -CO3 through chelation. Figure 1B
C H OH- and HCOOH-added solutions were 7.2 and 1.7,
2 5
2
shows UV/Vis absorption spectra of TiO and Au/TiO , and
respectively. Thus, HCOOH works as not only a good
electron donor but also as a pH-regulating agent. Gas
2
2
the solar spectrum. While rutile TiO only has absorption at
2
l < 410 nm, the Au NP loading induces strong and broad
chromatography confirmed the formation of CO during the
2
absorption due to the localized surface plasmon resonance
reaction (Figure S2). The total reaction is exergonic, and
written by Equation (2).
(
LSPR) in the visible region. The LSPR peaks for S-Au/TiO2
and L-Au/TiO2 are located around 550 nm and 580 nm,
0
ꢁ1
respectively. The spectrum of BM-Au/TiO is likely the sum
O
2
þ HCOOH ! H
2
O
2
þ CO
2
D
r
G ¼ ꢁ153:4 kJ mol
ð2Þ
2
of the absorptions of S-Au/TiO2 and L-Au/TiO2 with an
apparent LSPR peak at 566 nm, well matching with the solar
2
ꢁ
Surprisingly, BM-Au/TiO -CO3 exhibits much higher
activity than BM-Au/TiO under the same conditions, and the
H O concentration increases with an increase in t . Since the
2
2
ꢁ
ꢁ
spectrum. The spectrum hardly changes with the CO3
adsorption, which also supports the conclusion that CO3
2
2
2
2
p
ions are selectively adsorbed on the TiO surface of BM-Au/
pH of the solution remained at 1.7, the possibility can be
2
2
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excluded that the carbonate effect is due to a pH change.
without O and H O . The E with O and H O remains
2 2 2 on 2 2 2
The photocatalytic activities of the Au/TiO samples were
examined in the presence of 4% HCOOH. Figure 2B
+ 0.2 V. These results indicate that the reductions start for
H O at + 0.2 V [E (H O )], for O at + 0 V [E (O )], and
2
2
2
on
2
2
2
on
ꢁ
2
2
compares the concentration of H O generated at t = 1 h.
for TiO2 at ꢁ0.1 V [E (TiO )]. In the CO -TiO /FTO
2
2
p
on
2
3
2
The H O concentration in the BM-Au/TiO system (640 ꢀ
electrode system, the current with O and H O significantly
2 2 2
2
2
2
6
0 mm) far exceeds the sum of the H O concentrations in S-
decreases, and the Eon is almost in agreement with the
E (O ). Also, the value with O and without H O is rather
2
2
Au/TiO (50 mm) and L-Au/TiO (75 mm). Further, in the BM-
2
2
on
2
2
2
2
2
ꢁ
Au/TiO -CO3 system, the H O concentration reaches about
close to the E (TiO ). Clearly, the surface modification with
on 2
2
2
2
2
ꢁ
1
mm. Further, the reaction was performed in the BM-Au/
CO3 ions effectively suppresses the reductions of H O by
2 2
2
ꢁ
TiO -CO3 system using a green light emitting diode as
the TiO /FTO electrode.
2
2
a light source, and a quantum efficiency was calculated from
Further to clarify which of S- and L-Au NPs acts as the
the equation of F = 2 ꢀ (molecule number of H O formed)/
oxidation site in BM-Au/TiO , we carried out photoelectro-
2
2
2
(
incident photon number ) to be 5.4% at l = 530 nm.
chemical (PEC) measurements by using S- and L-Au/TiO2
The life time as well as the activity is the key factor for the
nanocrystalline films formed on FTO (Au/TiO /FTO) as the
2
catalysts. To examine the stability of the BM-Au/TiO photo-
photoanode (see the Supporting Information). A three-
2
catalyst, recycle experiments were carried out (Figure S3).
When the catalyst was not washed after the reaction, the
activity gradually decreased with an increase in the recycle
number (N). Then, the catalyst was reused by washing with
water after each run. Unexpectedly, the photocatalytic
activity increases at N = 2 to be maintained at least N ꢂ 5.
These intriguing results are discussed in more detail later in
connection with the action mechanism of the present
plasmonic photocatalyst.
electrode PEC cell with the structure of photoanode j Ag/
AgCl (reference electrode) j 0.1m NaClO electrolyte solution
4
containing 4% HCOOH j glassy carbon (cathode) was fab-
ricated. In the photocurrent time curves for the S- and L-Au/
TiO /FTO photoanode cells at the rest potential in the dark,
2
irradiation of visible light (l > 430 nm) causes anodic photo-
current in each system (Figure S4). A much larger photo-
current is observed for the S-Au/TiO /FTO system than the L-
2
Au/TiO /FTO system. As suggested by the results on the
2
Mesoporous TiO nanocrystalline films were formed on
particulate system, HCOOH should be oxidized on the
2
fluorine-doped tin oxide electrodes (TiO /FTO) by the doctor
surface of Au NPs of the Au/TiO /FTO photoanode, while
2
2
2
ꢁ
blade method (see the Supporting Information), and CO
O is reduced at the cathode in this PEC cell. The action
3
2
2
ꢁ
ions were chemisorbed on the surface (CO3 -TiO /FTO). To
spectrum is also important for elucidating the reaction
mechanism. The action spectra of the incident photon-to-
2
gain information about the surface modification effect by
2
ꢁ
CO3 ions, electrochemical (EC) measurements were carried
current efficiency (IPCE) for the Au/TiO /FTO photoanode
2
out for a three-electrode EC cell containing the TiO /FTO
structure with and without carbonate surface modification
cells were measured using optical filters with varying cut-off
2
[26]
wavelength. Figure 3B shows the action spectra of IPCE
for the present PEC cells, and the absorption spectra of the
photoanodes for comparison. The IPCE value for the S-Au/
(
0
working electrode) j Ag/AgCl (reference electrode) j aerated
.1m NaClO aqueous solution with and without 1 mm H O j
4
2
2
glassy carbon (counter electrode). Figure 3A shows linear
sweep voltammograms for the TiO /FTO and CO3 -TiO2/
TiO /FTO system is significantly larger than that for the L-
2
2
ꢁ
Au/TiO /FTO system in the 475–660 nm range. The IPCE in
2
2
FTO electrodes in the absence and presence of O and H O .
each system increases with decreasing wavelength of incident
light with only a weak shoulder near the LSPR peak, whereas
a peak is observed near the LSPR-peak wavelength in the
action spectra for several Au/MO-plasmonic photocatalytic
2
2
2
In the unmodified TiO /FTO electrode system, the current
2
onset potential (E ) is located at ꢁ0.1 V without O and
on
2
H O , at 0 V with O and without H O , and at + 0.2 V
2
2
2
2
2
[
14,15,17,27]
reactions.
been reported for the water oxidation by a PEC cell
A similar action spectrum has recently
[28]
employing Au/SrTiO as the photoanode. The absorption
3
intensity of the interband transition monotonically increases
with decreasing wavelength, and thus, the reaction may be
triggered by the excitation of the 5d-6sp transition of Au NP
in addition to its LSPR. These results are consistent with the
previous conclusion that the excited electrons are transferred
[18]
from S-Au NPs to L-Au NPs by way of TiO2. As a result of
the decrease in d from 10.6 to 2.3 nm, the density of states
[
29]
(
DOS) of Au NPs greatly lowers. While in the small Au
Figure 3. A) Dark current–potential (E/V vs. standard hydrogen elec-
NPs, the small DOS increases the entropic driving force for
trode, SHE) curves for TiO /FTO electrodes without and with the
the forward electron transfer from Au NP to TiO with that
2
2
carbonate surface modification in 0.1m NaClO aqueous solution in
4
for the back electron transfer simultaneously decreased, the
the absence and presence of O and 1 mm H O (pHꢃ6.2). B) IPCE
[30]
2
2
2
opposite situation is valid for L-Au NPs. The difference in
action spectra for the three-electrode PEC cells with a structure of S-
the entropic driving force for the electron transfer at the S-Au
NP/TiO and the L-Au NP/TiO interfaces rationalizes the
Au/TiO /FTO and L-Au/TiO /FTO (photoanode)jAg/AgCl (reference
2
2
electrode)j0.1m NaClO electrolyte solution containing 4% formic
2
2
4
electron transport from S-Au NPs to L-Au NPs through TiO2
acidjglassy carbon (cathode), and the absorption spectra for the
photoanodes for comparison.
in BM-Au/TiO2.
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3
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Angewandte
Communications
Chemie
2
ꢁ
On the basis of these results above, the mechanism of the
BM-Au/TiO plasmonic photocatalyzed-reduction of O to
CO3 would stem from the compatibility of the effective
charge separation in the BM-Au/TiO heterostructure and the
2
2
2
H O is proposed (Scheme 2). Visible-light irradiation of BM-
suppression of the TiO surface-mediated H O decomposi-
tion by the surface modification with CO3 ions. The reaction
2
2
2
2
2
2ꢁ
Au/TiO gives rise to the interfacial electron transfer from
2
small-to-large Au NP through the conduction band (CB) of
in the presence of HCOOH yields CO [Eq. (2)], which could
2
partly be adsorbed on the TiO surface during the reaction.
2
These considerations explain the increase in the activity at
N ꢄ 2 (Figure S3). The surface-fluorination of TiO was
2
previously reported to be effective in increasing the H O
concentration under irradiation of UV light.
2
2
[37,38]
In summary, this study has shown that irradiation of
visible light (l > 430 nm) of BM-Au/TiO in aerated pure
2
water yields 35 mm H O , and the generation of a millimolar
2
2
level of H O with a F value of 5.4% at l = 530 nm has been
2
2
2
ꢁ
achieved in the BM-Au/TiO -CO3 system with HCOOH as
2
an electron donor. We anticipate that this study presents the
useful information about the design of the photocatalyst for
the solar H O synthesis.
2
2
Scheme 2. A mechanism proposed for the BM-Au/TiO -
2
Acknowledgements
2ꢁ
CO3 plasmonic photocatalyzed-reduction of O to H O .
2
2
2
This work was partially supported by a Grant-in-Aid for
Scientific Research (C) (grant number 15K05654) and
MEXT-Supported Program for the Strategic Research Foun-
dation at Private Universities.
[
18]
TiO2. The Fermi energy (E ) of S-Au NPs lowers, while the
F
EF of L-Au NPs rises up. As a result, the oxidizing and
reducing abilities are induced on S- and L-Au NPs, respec-
+
tively. In pure water, H O is oxidized to O and H on the S-
Keywords: hydrogen peroxide · oxygen reduction reaction ·
2
2
Au NP surface of Au/TiO , of which visible-light activity
steeply increases at the Au mean particle size < 4 nm. In the
plasmonics · photocatalysis · solar chemical transformations
2
[30]
presence of HCOOH, it is preferentially oxidized to CO and
2
+
H
on the S-Au NP surface. On the other hand, the ORR
proceeds on the L-Au NP surface. Thermodynamically, the
potential of the electrons in the CB of rutile TiO (flat-band
2
[31]
[1] K. Sato, M. Aoki, R. Noyori, Science 1998, 281, 1646 – 1647.
potential, E =+ 0.04 V at pH 1.0 vs. SHE) is insufficient
fb
[
2] Y. Yamada, S. Yoshida, T. Honda, S. Fukuzumi, Energy Environ.
0
for the one-electron ORR (E (O /HO ) = ꢁ0.046 V vs.
2
2
Sci. 2011, 4, 2822 – 2825.
[
32]
SHE)
to proceed, but is sufficient for the two-electron
[
3] H. Reidl, G. Pfleiderer, Hydrogen peroxide. US Pat. 2215883,
0
[32]
ORR (E (O /H O ) =+ 0.695 V vs. SHE). In this system,
2
2
2
1940.
[
33]
due to the electron pool effect and electrocatalysis for the
two-electron ORR of the L-Au NP, O would be effectively
[4] J. M. Campos-Martin, G. Blanco-Brieva, J. L. G. Fierro, Angew.
Chem. Int. Ed. 2006, 45, 6962 – 6984; Angew. Chem. 2006, 118,
[
34]
2
7
116 – 7139.
[5] R. Cai, Y. Kubota, A. Fujishima, J. Catal. 2003, 219, 214 – 218.
6] M. Teranishi, S. Naya, H. Tada, J. Am. Chem. Soc. 2010, 132,
850 – 7851.
reduced to H O on the surface. Similar effects have been
2
2
II
II
suggested for the Cu ions in a visible-light-responsive Cu -
grafted rutile TiO system. Eventually, in the BM-Au/TiO2
[
[
35]
2
7
system, S-Au NPs highly dispersed on TiO2 work as an
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Received: July 11, 2016
Revised: August 2, 2016
Published online: && &&, &&&&
Angew. Chem. Int. Ed. 2016, 55, 1 – 6
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
5
These are not the final page numbers!

Angewandte
Communications
Chemie
Communications
Plasmonic Photocatalysis
Solar hydrogen peroxide formation:
Hydrogen peroxide was produced from
molecular oxygen at millimolar level over
bimodal gold-nanoparticle-decorated
rutile by visible-light irradiation (see pic-
ture). Formic acid was used as electron
donor and carbonate molecules were
absorbed onto the rutile surface to min-
imize the simultaneous loss of hydrogen
peroxide (LSPR=localized surface plas-
mon resonance).
M. Teranishi, R. Hoshino, S. Naya,
H. Tada*
&&&& — &&&&
Gold-Nanoparticle-Loaded Carbonate-
Modified Titanium(IV) Oxide Surface:
Visible-Light-Driven Formation of
Hydrogen Peroxide from Oxygen
6
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ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2016, 55, 1 – 6
These are not the final page numbers!