On-Demand Synthesis of H2O2 by Water Oxidation for Sustainable Resource Production and Organic Pollutant Degradation

Article abstract of DOI:10.1002/anie.202008031

H₂O₂ is a versatile and environmentally friendly chemical involved in water treatment, such as advanced oxidation processes. Anthraquinone oxidation is widely used for large-scale production of H₂O₂, which requires significant energy input and periodic replacement of the carrier molecule. H₂O₂ production should be customized considering the specific usage scenario. Electrochemical synthesis of H₂O₂ can be adopted as alternatives to traditional method, which avoids concentration, transportation, and storage processes. Herein, we identified Bi₂WO₆:Mo as a low-cost and high-selectivity choice from a series of Bi-based oxides for H₂O₂ generation via two-electron water oxidation reaction. It can continuously provide H₂O₂ for in situ degradation of persistent pollutants in aqueous solution. Clean energy from H₂ can also be produced at the cathode. This kind of water splitting producing sustainable resources of H₂O₂ and H₂ is an advance in environmental treatment and energy science.

Full text of DOI:10.1002/anie.202008031

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Accepted Article
Title: On-Demand Synthesis of H2O2 by Water Oxidation for
Sustainable Resource Production and Organic Pollutant
Degradation
Authors: Lejing Li, Zhuofeng Hu, and Jimmy C. Yu
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10.1002/anie.202008031
Angewandte Chemie International Edition
RESEARCH ARTICLE
On-Demand Synthesis of H2O2 by Water Oxidation for Sustainable
Resource Production and Organic Pollutant Degradation
Lejing Li,[a] Zhuofeng Hu,*[b] and Jimmy C. Yu*[a]
[a]
Prof. Jimmy C. Yu, Lejing Li
Department of Chemistry
The Chinese University of Hong Kong
Shatin, New Territories, Hong Kong, China
E-mail: jimyu@cuhk.edu.hk
[b]
Prof. Zhuofeng Hu
School of Environmental Science and Engineering
Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University
Guangzhou 510275, China
E-mail: huzhf8@mail.sysu.edu.cn
Supporting information for this article is given via a link at the end of the document.
Abstract: H2O2 is a versatile and environmentally friendly chemical
involved in water treatment, such as advanced oxidation processes.
Anthraquinone oxidation is widely used for large-scale production of
H2O2, which requires significant energy input and periodic
replacement of the carrier molecule. H2O2 production method should
be customized considering the specific usage scenario.
Electrochemical synthesis of H2O2 can be adopted as alternatives to
traditional method, which avoids the concentration, transportation and
storage processes. Herein, we identified Bi2WO6:Mo as a low-cost
and high-selectivity choice from a series of Bi based oxide electrodes
for H2O2 generation via 2-electron water oxidation reaction. It can
continuously provide H2O2 for in situ degradation of persistent
pollutants in aqueous. Simultaneously, clean energy of H2 can be
produced at the cathode. This kind of water splitting producing
sustainable resources of H2O2 and H2 presents an advance in
environmental treatment and energy science.
generate H2O2 avoiding the cost of plant building and the
transportation of concentrated H2O2, which is suitable for water
purification in remote areas. The widely studied way for the
electrochemical generation of H2O2 is two-electron oxygen
reduction reaction (ORR, Eq. 1).[4]
O2 + 2H+ + 2e- → H2O2 Eo = +0.70 V vs. RHE
Eq. 1
However, for the two-electron ORR method, the low solubility of
oxygen in water limits the mass transfer process in the
electrochemical reaction. Bubbling process is necessary to
induce oxygen in the solution. However, the bubbling process
often accounts for a large portion of cost in environmental
remediation process. These largely limit its further application for
AOPs. Moreover, two-electron ORR method often requires noble
metal catalysts such as Au, Pt, or Pd to obtain high efficiency.[1, 5]
The selectivity of two-electron ORR is reported to decrease at
large current density conditions.[5] Therefore, it is highly desirable
to combine yield and selectivity and to develop a new strategy for
onsite H2O2 generation.
In our opinion, electrochemical two-electron water oxidation (Eq.
2) process provides a straightforward route for H2O2 production.
Introduction
2H2O → H2O2 + 2(H+ + e-) Eo = +1.76 V vs. RHE
Eq. 2
Worldwide H2O2 production is approximately 3 million tons per
year. 60% is used for bleaching in the pulp，paper and textile
industry. Anthraquinone oxidation (AO) has been considered as
the mainstream production method for H2O2 since it was firstly
introduced in the 1940s.[1] It involves sequential hydrogenation
and oxidation steps of the anthraquinone, H2O2 extraction and
treatment of the working solution.[1-2] However, this method has
three main drawbacks: 1) the regeneration of anthraquinone
solution and hydrogenation of Pd catalysts make AO an energy-
demanding and resource-consuming process; 2) it requires large
infrastructures and impurity removal processes; 3) the
concentration process is required to reduce transportation costs.
The storage and transportation of concentrated H2O2 also
encounter security issues.
Various production methods should be developed to meet the use
of H2O2 in different occasions. For example, for the advanced
oxidation processes (AOPs), onsite preparation of H2O2 is much
more attractive than transporting concentrated H2O2. AOPs only
require the concentration of H2O2 to be about 1–10 wt.%, which
can be achieved by onsite production.[3] Electrochemical
synthesis is considered as a promising route for the onsite
production of H2O2. Portable electrochemical devices can
This electrochemical reaction offers an economical and practical
way for H2O2 generation. It only requires water as the reactant.
Therefore, it can avoid the gas bubbling process, which lowers
the production cost. Compared with oxygen reduction that
requires cathode materials, electrochemical two-electron water
oxidation is on the base of anode materials. Most of anode
materials used for oxidative production are metal oxides, which
are much cheaper than cathode materials of noble metal catalysts.
More importantly, metal oxides are often proved to be stable
within a large potential window. This is of great significance to
environmental remediation because it often requires the electrode
to operate for a long time.[6] Therefore, two-electron water
oxidation is a promising strategy for environmental remediation.
The two-electron oxidation reaction of water has been examined
[4f,
over some metal oxides
7]. For example, BiVO4 has been
identified as a suitable compound for H2O2 generation.[8] BiVO4
can achieve a Faraday efficiency (FE) above 70% at around 3.1
9]
V vs. RHE.[4g,
However, the BiVO4 suffered from high
overpotential (~ 400 mV) and poor durability due to the dissolution
of VO43- anions, which renders it not suitable for AOPs that need
to last for a certain period.[9] Therefore, catalyst design should
meet the requirements for both aspects: the selectivity towards
1
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RESEARCH ARTICLE
Figure 1 a) Scheme diagram for the preparation process for five Bi-based oxide electrodes. b) XRD pattern of the as-prepared FTO/Bi2WO6:Mo electrode(pink
pattern) as well as the pattern of FTO and the standard diffraction of Bi2WO6 for comparison. c) and d) Top-view SEM images of hierarchical flower-like structures
of Bi2WO6:Mo. e) TEM image, f) HRTEM image and g) SAED for Bi2WO6:Mo nanosheet.
H2O2 generation and the stability.
diagram of the preparation was shown in Figure 1a, which started
from the bismuth metal electrode. We then investigated the
activity trend of five electrodes towards oxidative H2O2 generation.
From the current-voltage curves (J-V curves, Figure S1a), the
current density of water oxidation reaction increases in the
sequence of FTO/Bi2O3, FTO/Bi2WO6, FTO/BiVO4, FTO/Bi2MoO6,
FTO/BiFeO3. We identified that OER is the dominant reaction
over the surface of FTO/BiFeO3 since the current rose below the
thermodynamic potential 1.76 V vs. RHE for 2-electron oxidation
of H2O.[4e, 5] The FE and H2O2 yield of these electrodes were
quantified and compared after operation at 2.6 V vs. RHE for
several minutes (Figure S1b): only FTO/Bi2O3, FTO/Bi2WO6,
FTO/BiVO4 show preference toward H2O2 formation. Overall,
considering the low production rate of FTO/Bi2O3 and the
instability of FTO/BiVO4 (I-T curve shown in Figure S2) in this
alkaline condition, Bi2WO6 achieves the best H2O2
electrosynthesis in terms of selectivity, H2O2 yield and stability
among all the Bi-based ternary oxides. Next, morphology
optimization and Mo-doping were adopted to further increase the
current density of Bi2WO6. Bi2WO6:5%Mo nanosheet with large
In this contribution, from a series of Bi based oxide electrodes, we
discover that Bi2WO6 was a satisfying electrode for 2-electron
water ocidation reaction in terms of the FE, overpotential and
durability. Then, the current density was enhanced by Mo-doping
and enlarging the surface area. This FTO/Bi2WO6:Mo electrode
achieves a peak FE of around 79% at 3.2 V vs. RHE, and can
keep a current density of 10 mA cm-2 for at least 6 hours. Clean
energy H2 was generated at the cathode with high current
efficiency. This work also provides a new strategy for in situ AOPs
on the base of H2O2 produced by via electrochemical water
oxidation. Persistent pollutants of norfloxacin (NFX) and
methyl blue (MB) can be effectively removed in the electrolytic cell
as continuous H2O2 generated from Bi2WO6:Mo anode.
Results and Discussion
Firstly, a series of Bi-based oxide electrodes were prepared
(details can be found in Supporting Information). The schematic
2
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Figure 2. a) Current density versus potential curves for electrodes FTO/Bi2WO6 and FTO/Bi2WO6:5%Mo. b) FE measurements collected at various constant applied
potentials for FTO/Bi2WO6:5%Mo. c) Stability test of J-T curves under different biases. d) Accumulated H2O2 concentration at 2.4 V vs. RHE. e) In situ Raman
spectra recorded during the potentiostatic current-time tests at the potential from 2.0 V to 2.6 V vs. RHE. f) The FE of H2 evolution at cathode at different cell voltage.
surface area was converted from WO3:5%Mo plate-like array
(Figure S3). The XRD result (Figure 1a) reveals that the as-
prepared FTO/Bi2WO6:5%Mo is in accordance with the
orthorhombic bismuth tungstate (PDF#73 2020). This also
indicates the conversion of Bi2WO6:5% from WO3:5% has been
achieved by the second hydrothermal treatment. From SEM
images presented in Figures 1b, c and Figure S4, both Bi2WO6
and Bi2WO6:5%Mo appears with hierarchical flower-like
structures by self-assembly nanosheets with a thickness about 10
~ 20 nm. The average diameter of the nanoflowers is determined
to be 1-2 μm. Then exposed facet of Bi2WO6:5%Mo nanosheets
was further determined by TEM technique (Figures 1d-f). A part
of the well-dispersed nanosheet is displayed in Figure 1d, and the
high-resolution TEM (HRTEM) image (Figure 1e) reveals two sets
of lattice fringes with an interplanar spacing of 0.274 and 0.276
nm, which corresponding to the (020) and (200) planes,
respectively. The selected area electron diffraction (SAED, Figure
1f) pattern confirms the orthorhombic structure with (001) oriented
growth. Other diffraction spots are also indexed to corresponding
planes indicated. The surface chemical composition and valence
state were characterized by XPS and shown in Figure S5. From
the XPS spectrum of Mo (inset of Figure S5a), the energy
difference between 4f5/2 and 4f7/2 is about 3.2 eV, implying the
chemical state of doped Mo is +6.[10]
The current-voltage (J-V) curves were recorded to evaluate the
electrocatalytic performance of pure Bi2WO6, Mo doped Bi2WO6
and bare FTO (Figure 2a). Bi2WO6 shows a lower onset potential
and a higher current density than FTO. The current density is
further increased after Mo-doping and reaches 0.2 mA cm-2 at 2.0
V vs. RHE. The substitution of W by Mo induces slight
modification of the crystal structure and d electronic configuration,
which affects the charge transfer property.[11] The charge transfer
3
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resistance of electrodes with and without Mo-doping were
evaluated according to electrochemical impedance spectroscopy
(EIS) shown in Figure S6. The diameter of the semicircle in
Nyquist plots becomes much smaller after Mo-doping, indicating
a higher charge transfer rate, which contributes to higher current
density.
when the cell voltage above 2.3 V. Thus, clean energy of H2 was
produced simultaneously at the cathode. Therefore, this
electrochemical system for water splitting can provide valuable
chemical of H2O2 and H2 simultaneously.
Then we try to understand mechanism for the high selectivity of
water oxidation reaction over the surface of Bi2WO6:Mo. As
reported before, a ΔGOH* between 1.6 and 2.4 eV is favorable to
H2O2 production.[4g] A small ΔGOH* often leads to weak OH*
bonding energy and O2 evolution is more likely to happen.[9, 16]
·OH formation is more likely to occur on catalysts with strong OH*
bonding free energy ( Δ GOH*). By using density function
calculation, we construct Bi2WO6 and Mo-doped Bi2WO6 as
shown in a, b and c of Figure 3. In the model of Mo-doped Bi2WO6,
the OH intermediate is located near the Mo or W sites for
investigation (Figure 3b and c). They are denoted as
Bi2W(Mo)O6:Mo and Bi2W(W)O6:Mo. The ΔGOH* is calculated to
1.62 eV for Bi2W(W)O6, 1.41 eV for Bi2W(Mo)O6:Mo and 1.93 eV
The H2O2 production reaction must compete with the four-electron
oxidation reaction (oxygen evolution, Eq. 3) and the one-electron
oxidation reaction (·OH, hydroxyl radical generation, Eq. 4).
2H2O → O2 + 4(H+ + e-) Eo = +1.23 V vs. RHE
H2O → ·OH + (H+ + e-) Eo = +2.38 V vs. RHE
Eq. 3
Eq. 4
Our electrode can achieve a high selectivity and stability toward
H2O2 generation. Then faradaic efficiency of FTO/Bi2WO6:5%Mo
towards H2O2 generation is further quantified as a function of
potentials. Figure 2b shows that the 2-electron-WOR is the
predominant reaction in the bias window of 2.6 ~ 3.4 V vs. RHE
in KHCO3 electrolyte, and the peak of FE reaches 79% at 3.2 V
vs. RHE over Bi2WO6:5%Mo surface. The FE for both
FTO/Bi2WO6:5%Mo and bare FTO electrode shows a similar
trend: increasing firstly to the maximum and then decreasing over
the tested range. Also, the H2O2 generation rate as a function of
bias was tested (purple curve in Figure 2b), and it achieves the
maximum about 300 µmol h-1 cm-2 at 3.4 V vs. RHE.
The effect of electrolyte on the selectivity of water oxidation was
also investigated in other electrolytes (1 M KH2PO4, 1 M K2HPO4
and 1 M K2CO3). We found Bi2WO6:Mo achieves the highest H2O2
generation in KHCO3 (Figure S7), and higher concentration of
KHCO3 facilitates both the current density and FE (Figure S8).
for Bi2W(W)O6:Mo. The ΔGOH* for Bi2W(W)O6 and Bi2W(W)O6:Mo
17]
are in the favorable range for H2O2 evolution,[4g,
which is
beneficial to the H2O2 evolution. However, compared with
Bi2W(Mo)O6:Mo with ΔGOH* of 1.41 eV, Bi2W(W)O6:Mo shows a
better ΔGOH* of 1.93 eV. The ΔGOH* of OH* locates in the middle
of the H2O2 evolution range when the OH* is situated at the W
sites. This indicates that the W atoms in the Mo-doped
Bi2W(Mo)O6 should be the reaction center.
2-
12]
The role of HCO3 has been discussed previously.[7a,
It is
2-
proposed that adsorbed HCO3 can be firstly oxidized to
percarbonate intermediates (HCO4 or C2O62-), which can further
-
hydrolyzed in water to give H2O2.
The electrochemical stability is vitally important for H2O2
production materials, especially for those used in degradation
context for long-term service. A current-time (I-T) curve of
FTO/Bi2WO6:5%Mo was tested up to 6 hours under different bias
(Figure 2c). This electrode is quite stable at 2.4 V vs. RHE, while
current densities only undergo slight decrease when bias
increased to 2.8 V and even 3.4 V vs. RHE. To further quantify
the H2O2 generation capacity of FTO/Bi2WO6:5%Mo, onsite H2O2
concentration was measured under 2.4 V vs. RHE in 40 mL
electrolyte over 6 h as shown in Figure 2d. The accumulated
concentration reaches around 25 ppm in 6 hours. Additionally, the
J-V curve recorded after the stability test is very close to the
previous one (Figure S9), indicating robust durability for
FTO/Bi2WO6:5%Mo during H2O2 production. Additionally, Raman
spectra were collected during the potentiostatic current-time
experiments at different biases (2.0 V ~ 2.6 V vs. RHE) and shown
in Figure 2e. Based on previous researches, Raman bands at 790
cm-1 and 829 cm-1 were associated with the antisymmetric and
symmetric Ag modes of terminal O-W-O,[13] band at ~700 cm-1
was associated with the W-O stretching modes for equatorial
oxygens in WO6 octahedra,[14] bands at around 302 cm-1 was
ascribed to the bending vibration of WO6 as well as the stretching
and bending vibration of BiO6 polyhedra[15]. All Raman bands
remain unchanged positions during the electrochemical test
Figure 3. Structure of OH* on a) Bi2WO6, b) Mo-Bi2W(Mo)O6 and c) Mo-
Bi2W(W)O6. Blue atoms are Bi, red are O, orange W and green is Mo. d) Energy
diagram for H2O2 evolution on Mo-doped Bi2WO6.
At 0 V on the surface of Bi2W(W)O6:Mo, the theoretical equilibrium
potential for H2O2 is 1.76 V vs. RHE. As a two-electron reaction
process, the free energy for H2O2 evolution situates at 3.52 eV.[16]
At the equilibrium potential of 1.76 V vs. RHE, the first step for the
formation of OH* is uphill, and the second step is downhill. Hence,
the first step of forming the OH* intermediate is a rate limiting step.
Consequently, at the equilibrium potential, the H2O2 evolution is
not spontaneous. When the applied bias increase to 2.2 V (red
line in Figure 3d), as used in our experiments, the downhill in free
energy is more obvious. This is consistent with our experiments
that H2O2 is generated apparently at this bias.
The application of onsite produced H2O2 can be used for water
remediation, disinfection, and pulp bleaching. In this work, we
propose to use the onsite generated H2O2 to degrade persistent
pollutants of NFX (25 ppm) and dye of MB (25 ppm). NFX is an
antibiotic that belongs to the class of fluoroquinolone antibiotics,
and 75% of NFX is excreted from the human body and induces
the accumulation of antibiotics in aquatic ecosystems.[18]
Continuously accumulated NFX has been proved to interfere with
bacterial DNA replication and thereby leading to bacterial
genotoxicity.[19] Whether the pharmaceutical group of NFX can be
regardless of applied bias, indicating
a stable structure
characteristic of Bi2WO6:5%Mo in H2O2 generation.
While H2O2 was produced at the anode, a clean fuel H2 was
formed at the cathode simultaneously. As shown in Figure 2f, the
FE of H2 evolution at cathode exceeds 90% or even up to 100%
4
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Figure 4. a) Comparison of NFX removal performance of FTO and FTO/Bi2WO6:5%Mo. b) NFX removal comparison of FTO/Bi2WO6:5%Mo at different biases. c)
TOC removal over time using FTO/Bi2WO6:5%Mo as the working electrode at 3.0 V vs. RHE. d) The accumulative H2O2 concentration in the degradation system
with and without the existence of NFX. e) Accumulative ·OH generated in the onsite H2O2 production system. f) Effect of IPA scavenger on NFX degradation
performance using FTO/Bi2WO6:5%Mo as the working electrode.
attacked must be considered in assessing the efficiency of the
degradation pathway.
decolorization test was conducted and shown in Figures S10a
and b. Obvious color removal was observed with time when 2.4 V
vs. RHE bias was applied to FTO/Bi2WO6:5%Mo electrode. MB
polluted electrolyte becomes colorless after 2.5 h. Then bias
dependent NFX degradation performance was also investigated
as shown in Figure 4b. The faster NFX removal rate observed at
higher potential should be closely related to the higher
accumulated H2O2 concentration.From the HPLC chromatogram
(Figure S11), the new appeared peaks in the total ion current
indicate the newly formed intermediates transformed from NFX,
and these results demonstrate that the NFX molecule was
degraded into smaller molecules. These small molecules can be
further degraded to CO2 and water, as the final total organic
carbon (TOC) removal reaches up to ~88% after 4 h of electrolysis
of FTO/Bi2WO6:5%Mo at 3.0 V vs. RHE (Figure 4c).
During the NFX removal test, the soaked area of the working
electrode was 2 cm2, and a carbon rod was used as the counter
electrode. We first tested the NFX degradation efficiency in this
onsite H2O2 generation system. High performance liquid
chromatography (HPLC) was used to test the residual NFX and
other oxidation derivatives. Figure 4a shows the variation of
residual NFX (appeared at ~10 min in the Chromatogram) as a
function of time for the substrate FTO and electrode
FTO/Bi2WO6:5%Mo at 2.4 V vs. RHE. It shows a much faster
degradation rate for FTO/Bi2WO6:5%Mo compared with the FTO
substrate. With the continuous generation of H2O2, the NFX
concentration decreased rapidly and it was no longer detected
after 80 minutes for FTO/Bi2WO6:5%Mo. Meanwhile, the MB
5
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RESEARCH ARTICLE
Figure 5. The proposed degradation pathway for NFX in the onsite H2O2 synthetic system.
Subsequently, the H2O2 concentration in the onsite degradation
system was quantified with and without the addition of 25 ppm
NFX (Figure 4d). The accumulative concentration of H2O2
increases as a function of time regardless of whether NFX is
added. It reveals that almost half of the generated H2O2 was
consumed by the degradation process of NFX. Moreover, the
formation of ·OH in the degradation system generated by
H2O2 generation rate was further optimized by Mo-doping and
enlarged specific surface area. The FE of electrode FTO/
Bi2WO6:Mo reaches peak 79% at 3.2 V vs. RHE, and it also shows
good durability at least in 6 h. As revealed by DFT calculation, the
ΔGOH* value for both Bi2WO6 and Bi2WO6:Mo is favorable for a 2-
electron water oxidation reaction, and W atoms should be the
reaction center. As H2 evolution occurs at the cothode, this
Bi2WO6:Mo was confirmed by the fluorescence method (Fiure S12, electrolytic cell achieves a superior current efficiency with high-
ESI†). Figure 4e shows that the amount of accumulative ·OH
increases linearly. 2-propanol (IPA) was chosen as scavenger to
studies the contribution of ·OH for degradation. Figure 4f shows
the NFX removal efficiency was significantly affected by IPA,
suggesting ·OH is crucial for the degradation of NFX. The
FTO/Bi2WO6:Mo electrode continuously supplies H2O2 to degrade
NFX molecules, resulting in NFX degradation and mineralization
in this onsite H2O2 generation system.
value-added chemicals produced at both electrodes. Then the
degradation performance of the onsite generated H2O2 was
evaluated using NFX and MB as model pollutants. It gives
satisfying results in terms of removal rate and mineralization ratio
of NFX. Subsequently, the degradation intermediates were
identified by using the LC-MS technique and the degradation
routes were also analyzed based on the structure information on
the intermediates. This on-demand production approach allows
maximum utilization of H2O2 in a system.
Using the liquid chromatography-mass spectrometry (LC-MS)
technique, the mass spectra and structural formulas of 6
intermediate molecules (IA, IB, IC, ID, IE, IF) in this system were
analyzed in Figure S13. The structure of NFX consists of a
fluorine atom, a piperazine ring and the basic pharmacophore
quinolone group. The destruction of the quinolone group is the
key step to prevent the spread of antibiotic-resistance gene. Then
combining the LC-MS result and structural property of NFX, we
analyzed the structure of intermediates and proposed the
degradation pathways. As shown in Figure 5, the degradation
mainly occurs through two paths: quinolone group transformation
and piperazine ring cleavage. In pathway I, the quinolone was
opened at the unsaturated bond by hemolytic reaction, producing
m/z=352 through addition reaction. Followed by decarboxylation,
decarbonylation and hydroxylation reactions, the m/z=352 is
further oxidized to m/z=296. In pathway II, the piperazine ring is
firstly attacked at the tertiary amine (site II) and causing a ring-
opening reaction. Then, two methylenes are lost and intermediate
m/z=294 is generated. Subsequently, intermediate m/z=294 is
further oxidized via the loss of functional group –NH-CH2-CH2 to
produce intermediate m/z=251. Finally the m/z=233 is produced
by defluorination.
Acknowledgements
This work was supported by the Research Grants Council of Hong
Kong Special Administrative Region (project no 14304019), the
Hong Kong PhD Fellowship Scheme (PF17-10186). This work
was also supported by the Natural Science Foundation of
Guangdong Province, China (2019A1515012143), the National
Natural Science Foundation of China (Grant No. 51902357), the
Guangdong Basic and Applied Basic Research Foundation
(2019B1515120058), the Start-up Funds for High-Level Talents
of Sun Yat-sen University (38000-18841209) and the
Fundamental Research Funds for the Central Universities
(38000-31610622). The theoretical calculation is supported by
National supercomputer center in GuangZhou and National
supercomputing center in Shenzhen (Shenzhen cloud computing
center).
Keywords: electrocatalysis, hydrogen peroxide, water oxidation,
Bi2WO6:Mo, organic pollutant degradation
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In conclusion, we identified Bi2WO6 as a suitable electrode for
H2O2 production through a 2-electron water oxidation route. The
6
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RESEARCH ARTICLE
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10.1002/anie.202008031
Angewandte Chemie International Edition
RESEARCH ARTICLE
Entry for the Table of Contents
H2O2 is synthesized by direct electrochemical oxidation of water on the surface of Bi2WO6:Mo anode, which provides a straightforward
route for the onsite need of H2O2, such as advanced oxidation processes. Combined with the superior H2 evolution efficiency at the
cathode, this electrolytic cell enables sustainable resources produced at both electrodes.
8
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