Catalysis
of the Oxygen-Evolution
Reaction
in 1.0 M Sulfuric
Acid
by
Manganese
Antimonate
Films
Synthesized
via Chemical
Vapor
Deposition
Jacqueline
A. Dowling,
⊥
Zachary
P. Ifkovits,
⊥
Azhar
I. Carim,
Jake M. Evans,
Madeleine
C. Swint,
Alexandre
Z. Ye, Matthias
H. Richter,
Anna
X. Li, and Nathan
S. Lewis
*
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This:
ACS Appl.
Energy
Mater.
2024,
7, 4288−4293
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Supporting
Information
ABSTRACT:
Manganese
antimonate
(Mn
y
Sb
1
−
y
O
x
) electrocatalysts
for the oxygen-evolution
reaction
(OER)
were
synthesized
via
chemical
vapor
deposition.
Mn-rich
rutile
Mn
0.63
Sb
0.37
O
x
catalysts
on
fluorine-doped
tin oxide
(FTO)
supports
drove
the OER
for 168 h
(7 days)
at 10 mA cm
−
2
with a time-averaged
overpotential
of 687
±
9 mV and with
>97%
Faradaic
efficiency.
Time-dependent
anolyte
composition
analysis
revealed
the steady
dissolution
of Mn and Sb.
Extended
durability
analysis
confirmed
that
Mn-rich
Mn
y
Sb
1
−
y
O
x
materials
are more
active
but dissolve
at a faster
rate than
previously
reported
Sb-rich
Mn
y
Sb
1
−
y
O
x
alloys.
KEYWORDS:
electrolysis,
oxygen-evolution
reaction
in acid, manganese
antimony
oxide, earth-abundant
materials,
heterogeneous
catalysis,
chemical
vapor deposition
T
he electrochemical
oxygen-evolution
reaction
(OER)
is
an anodic
process
that
oxidizes
water,
an abundant
feedstock,
and can supply
electrons
necessary
to drive
many
fuel-forming
cathodic
processes
including
the production
of H
2
from
H
2
O, NH
3
from
N
2
, and hydrocarbons
from
CO
2
.
1
−
3
Water
electrolysis
for H
2
generation
specifically
is of interest
in
the storage
of energy
from
intermittent
renewable
sources.
4,5
Carbon-free
electricity
can drive
water
electrolysis
to generate
green
H
2
for use on demand.
6,7
Commercial
proton-exchange
membrane
(PEM)
electrolyzers
use Ir-based
catalysts
to effect
the oxygen-evolution
reaction
(OER)
in acidic
media.
8,9
IrO
x
exhibits
high
OER
activity
and durability,
but the low crustal
abundance
of Ir is a barrier
to scale.
10
−
14
An earth-abundant,
but less-active,
electrocatalyst
may
be an acceptable
replace-
ment
for IrO
x
in scenarios
with infrequent
electrolyzer
use and
low-cost
electricity.
10
Electrolyzers
paired
with
seasonal
or
multiyear
H
2
storage
in reliable
wind
and solar
systems
may
operate
at reduced
capacity
factors
(
∼
50%)
and capitalize
on
abundant,
otherwise-curtailed,
zero-cost
electricity
to drive
electrolysis.
5,10,15
A variety
of earth-abundant
materials
have
displayed
relatively
stable
oxygen-evolution
catalysis
in acidic
aqueous
electrolytes,
including
Mn-oxyhalides,
arc-melted
Ni
2
Ta
electrodes,
Co-doped
Fe
2
O
3
thin
films,
and
N
2
-doped
W-
carbide
nanoarrays.
16
−
19
Earth-abundant
Mn-rich
rutile
Mn
y
Sb
1
−
y
O
x
powders
are effective
catalysts
for chemical
oxygen-evolution
in acidic
media,
and
Sb-rich
rutile
Mn
y
Sb
1
−
y
O
x
sputtered
films
have
shown
promising
long-term
durability.
20,21
Rutile
Mn
y
Sb
1
−
y
O
x
(0.3 <
y
< 0.7) materials
are
more
active
and stable
than
nonrutile
Mn
y
Sb
1
−
y
O
x
materi-
als.
20
−
25
In this
work,
Mn
0.63
Sb
0.37
O
x
was
synthesized
via
chemical
vapor
deposition
(CVD).
CVD
is a scalable
synthetic
method
and may be an effective
approach
to controllably
coat
catalyst
layers
onto
high surface-area
supports,
including
those
suitable
for use in a PEM
electrolyzer.
26
The CVD
deposition
method
complements
previous
synthetic
routes
for generation
of Mn
y
Sb
1
−
y
O
x
including
sputtering,
bulk
powder
mixing,
and
electrodeposition.
20
−
23
Mn
0.63
Sb
0.37
O
x
thin
films
were
deposited
by CVD
on
fluorine-doped
tin oxide
(FTO)
substrates
using
30 super-
cycles
that each
consisted
of 10 SbO
x
subcycles
and 5 MnO
x
subcycles
(Scheme
1).
27
Each
chemical
vapor
deposition
subcycle
consisted
of a precursor
pulse
with
either
tris-
(dimethylamido)antimony(III)
(TDMA-Sb)
or bis-
(ethylcyclopentadienyl)-manganese
(Mn(EtCp)
2
), in addition
to an ozone
coreactant
pulse.
The growth
rates
of MnO
x
and
SbO
x
were
independently
measured
via ellipsometry
(Figure
Received:
January
17, 2024
Revised:
March
21, 2024
Accepted:
March
21, 2024
Published:
March
25,
2024
Letter
www.acsaem.org
© 2024
The Authors.
Published
by
American
Chemical
Society
4288
https://doi.org/10.1021/acsaem.4c00135
ACS Appl.
Energy
Mater.
2024,
7, 4288
−
4293
This article is licensed under CC-BY 4.0
1A).
The
MnO
x
thickness
increased
linearly
with
pulse
duration,
indicating
controlled
chemical
vapor
deposition,
whereas
the thickness
of the SbO
x
was constant
regardless
of
the pulse
duration,
indicating
self-limiting
atomic-layer
deposition.
28
The
Mn
−
Sb
binary
oxide
was formed
using
a
0.33 s pulse
of Mn(EtCp)
2
, which
corresponded
to 0.43 nm of
MnO
x
per cycle,
and
a 1 s pulse
of TDMA-Sb,
which
corresponded
to 0.12
nm of SbO
x
per cycle.
Inductively
coupled
plasma
mass
spectrometry
(ICP-MS)
indicated
that
the composition
of the as-deposited,
unannealed
catalyst
was
Mn/(Mn+Sb)
= 0.63
±
0.01.
After
annealing
in air for 6 h at
the maximum
tolerable
temperature
(600
°
C) of the TEC8
FTO
substrate,
grazing
incidence
X-ray
diffraction
(GIXRD)
analysis
of Mn
0.64
Sb
0.36
O
x
showed
reflections
at 2
θ
≈
27
°
, 35
°
,
53
°
, and 56
°
, consistent
with a rutile
crystal
structure
based
on
a comparison
to the reflections
of rutile
MnSb
2
O
6
.
20,21,23
A Mn
0.63
Sb
0.37
O
x
electrode
was subjected
to a 168 h (7 day)
durability
test at
J =
10 mA cm
−
2
in 1.0 M H
2
SO
4
(aq),
and the
OER
overpotential
(
η
) was recorded
(Figure
2A).
During
this
experiment,
the galvanostatic
hold
was interrupted
at 24 h
intervals,
and voltammetric
and impedance
data were
collected
after
30 s at open
circuit
(Figure
2B and Figure
S2).
The
measured
overpotentials
at
J =
10 mA cm
−
2
were
reduced
by
∼
14
mV to correct
for the uncompensated
ohmic
resistance
intrinsic
to the electrochemical
cell configuration.
The
time-
averaged
OER
overpotential
over the entire
test duration
was
η
= 687
±
9 mV (the blue shaded
region
in Figure
2A shows
the
standard
deviation).
However,
consistent
with
previous
results
for Mn
y
Sb
1
−
y
O
x
, during
the short
periods
at open
circuit,
as
well
as between
the first
and
second
voltametric
cycles
collected
in succession
at each
24 h interval,
the OER
overpotential
decreased
and the catalyst
“recovered”
(Figure
2A, Figure
S2B).
21,23
The OER
overpotential
at 10 mA cm
−
2
as
measured
from
the voltammetric
analyses
was
η
= 617 mV at
t
=
0 h and was
η
= 618 mV at
t =
168 h (Figure
2B, Figure
S2B).
Redox
waves
centered
at 1.46
V vs the reversible
hydrogen
electrode
(RHE)
appeared
and
increased
in
magnitude,
during
the extended
durability
test (Figure
2B,
Figure
S2A),
analogous
to the behavior
of Mn
y
Sb
1
−
y
O
x
electrocatalysts
deposited
by sputtering.
21
Aliquots
of the electrolyte
solution
were
taken
without
replacement
at
∼
24
h intervals,
and the dissolution
of Sb and
Mn was measured
by ICP-MS
during
the durability
test at 10
mA cm
−
2
in 1.0 M H
2
SO
4
(aq)
(Figure
2C).
The average
rate
of Sb dissolution
(11 weight
% per day, or 0.0013
μ
mol
cm
−
2
h
−
1
) was comparable
to the average
rate of Mn dissolution
(8%
per day,
or 0.0015
μ
mol
cm
−
2
h
−
1
) (Figure
S3).
The
dissolution
rate of both
metals
was lower
during
the initial
48 h of the
test
than
at later
time
points.
Another
Mn
0.63
Sb
0.37
O
x
electrode
from
the same
deposition
batch
yielded
an average
of 97.6%
Faradaic
efficiency
for oxygen
evolution
during
93 h of continuous
operation
at 10 mA cm
−
2
in 1.0 M H
2
SO
4
(Figure
2D).
Hence,
despite
the high Faradaic
efficiency
and a relatively
stable
OER
overpotential,
substantial
Scheme
1. (A) Synthesis
of Crystalline
Mn
0.63
Sb
0.37
O
x
via
Chemical
Vapor
Deposition
and
Annealing.
(B) Ternary
Chemical
Vapor
Deposition
with
TDMA-Sb
and Mn(EtCp)
2
Precursors,
in Addition
to Ozone
As a Coreactant
Figure
1.
(A) Growth
rates
of MnO
x
and SbO
x
via CVD
and ALD,
respectively,
derived
from
the analysis
of ellipsometry
data.
(B)
Grazing
incidence
X-ray
diffraction
(GIXRD)
data
acquired
from
Mn
0.64
Sb
0.36
O
x
and XRD
data acquired
from
the TEC8
FTO
substrate
after
annealing
in air for 6 h at 600
°
C.
ACS
Applied
Energy
Materials
www.acsaem.org
Letter
https://doi.org/10.1021/acsaem.4c00135
ACS Appl.
Energy
Mater.
2024,
7, 4288
−
4293
4289
catalyst
corrosion
occurred,
consistent
with
the behavior
of
sputtered
Mn-rich
alloys.
23,24
The
OER
overpotential
and
metal
dissolution
rates
of a replicate
electrode
that was tested
for 176 h (>7 days)
at 10 mA cm
−
2
in 1.0 M H
2
SO
4
were
in
agreement
with
that of the Mn
0.63
Sb
0.37
O
x
electrode
described
above
(Figure
S3).
An additional
Mn
0.63
Sb
0.37
O
x
electrode
was
operated
galvanostatically
at
J
= 100 mA cm
−
2
and was subjected
to
very positive
potentials
during
voltametric
analysis
(Figure
3).
The time-averaged
OER
overpotential
over a period
of 8.5 h at
J
= 100 mA cm
−
2
was 724
±
8 mV (Figure
3). Figure
S8
presents
an expanded
view
of the data in Figure
3 during
the
first 8 h of operation.
The overpotential
of the OER
at
J
= 100
mA cm
−
2
was 709 mV at
t
= 0 h and 688 mV at
t
= 8 h (Figure
3). In the first 8 h at
J
= 100 mA cm
−
2
in 1.0 M H
2
SO
4
, ICP-
MS indicated
more
leaching
of Sb than
of Mn (Figure
3C).
The chronopotentiometry
experiment
at 100 mA cm
−
2
in 1.0
M H
2
SO
4
was continued
for 26 h, with
periodic
interruptions
due to bubble
formation
that
inhibited
current
flow
at the
counter
electrode
(Figure
3). Voltammetric
analysis
indicated
that the initial
OER
overpotential
at
J
= 350 mA cm
−
2
was 819
mV in 1.0 M H
2
SO
4
(Figure
S9).
The Mn
0.63
Sb
0.37
O
x
electrode
was characterized
before
and
after the 168 h of the OER
durability
test at
J =
10 mA cm
−
2
in
1.0 M H
2
SO
4
(aq)
by scanning
electron
microscopy
(SEM),
electrochemical
impedance
spectroscopy
(EIS),
energy
dis-
persive
X-ray
spectroscopy
(EDX),
and X-ray
photoelectron
spectroscopy
(XPS).
The
SEM
data
showed
a conformal
coating
of the catalyst
on the substrate
prior
to the OER,
and
EIS measurements
(Figure
S4B and C, respectively)
indicated
an
∼
22-fold
increase
in surface
roughness
during
the 168 h
durability
test (Figure
S5).
Notably,
although
the material
dissolved,
the overpotential
required
to produce
J
= 10 mA
cm
−
2
did not change
substantially
during
this time.
The redox
waves
observed
at
∼
1.46
V vs RHE
(Figure
2B)
in the voltammetric
data are consistent
with behavior
of MnO
x
and
other
Mn
y
Sb
1
−
y
O
x
materials.
21,29
XP spectra
of the
Mn
0.63
Sb
0.37
O
x
catalyst
material
acquired
before
and after
the
168 h OER
durability
test at
J =
10 mA cm
−
2
in 1.0 M
H
2
SO
4
(aq)
indicated
that the material
was always
principally
composed
of Mn(III)
with
some
Mn(IV)
observable
(
∼
20%)
after
operation,
consistent
with previous
analysis
of antimonate
systems
(Figure
S6, Figure
S7, Table
S3).
23
Sb sites
in binary
oxide
materials
are inactive
for the OER
reaction,
21,23,24
consistent
with
the OER
being
localized
on Mn sites
and
mediated
by Mn redox
events,
with
Sb
5+
ions contributing
to
electrochemical
stability.
21
−
23
Electrocatalytically
inactive
Sb
5+
sites
may
stabilize
Mn sites
that actively
effect
the OER
by
inducing
enhanced
hybridization
of the O p-orbital
and Mn d-
orbital.
23,24
The
Mn metal
fraction
as indicated
by energy-
dispersive
X-ray
(EDX)
spectroscopy
decreased
from
64
±
5%
before
operation
to 49
±
7% after
168 h at
J
= 10 mA cm
−
2
(Figure
S4A).
XP spectra
of the Sb 3d region
indicated
a shift
from
3.2 to 5.0 in the Sb oxidation
state
(Figure
S6, Figure
S7C,
and Table
S3). Mn-rich
alloys
are thus expected
to be less
stable
than
Sb-rich
alloys,
consistent
with the substantial
metal
dissolution
of the Mn
0.63
Sb
0.37
O
x
catalysts
observed
during
the
multiday
durability
test (Figure
2). However,
some
degree
of
Figure
2.
Electrochemical
activity,
stability,
and Faradaic
efficiency
of Mn
0.63
Sb
0.37
O
x
during
the OER
at
J
= 10 mA cm
−
2
for 168 h (7 days)
in 1.0
M H
2
SO
4
(aq).
(A) Time
dependence
of the OER
overpotential
after
correction
for the uncompensated
resistance
of the cell. (B) Cyclic
voltammograms
(
v
= 40 mV s
−
1
) collected
after
t
= 0 h and after
t
= 168 h of the galvanostatic
hold.
(C) Amount
of dissolved
metal
in the anolyte
as quantified
by ICP-MS,
as a percentage
of the total
deposited
Sb and total
deposited
Mn. (D) Eudiometric
measurement
of the level
of O
2
(g)
production.
ACS
Applied
Energy
Materials
www.acsaem.org
Letter
https://doi.org/10.1021/acsaem.4c00135
ACS Appl.
Energy
Mater.
2024,
7, 4288
−
4293
4290
electronic
stabilization
of Mn sites by Sb ions may account
for
the enhanced
corrosion
resistance
observed
herein
relative
to
that reported
for unary
Mn oxide
materials.
23,24
In summary,
the extended
durability
of rutile
Mn
0.63
Sb
0.37
O
x
catalysts
was assessed
during
galvanostatic
operation
at
J
= 10
mA cm
−
2
and at
J
= 100 mA cm
−
2
in 1.0 M H
2
SO
4
. After
168 h
of operation
at
J
= 10 mA cm
−
2
, a loss of electrocatalyst
mass,
an increase
in porosity,
and partial
oxidation
of the constituent
Mn were
observed
relative
to the as-prepared
material.
A lower
overpotential
was observed
for the Mn-rich
alloy
at
J =
10 mA
cm
−
2
than previously
reported
for Sb-rich
Mn
y
Sb
1
−
y
O
x
alloys.
21
However,
unlike
the Sb-rich
Mn
y
Sb
1
−
y
O
x
alloys,
Mn
0.63
Sb
0.37
O
x
catalysts
corroded
continuously
during
operation.
This
behavior
is consistent
with
the notion
that Sb stabilizes
Mn
sites,
as well as with
prior
results
on the behavior
of Mn-rich
alloys
prepared
by sputtering.
23,24
The
extended
duration
testing
reported
here,
along
with
previous
reports,
confirm
an
activity-stability
trade-off
across
the Mn:Sb
composition
space.
30
A reduced
Mn:Sb
ratio
may thus enhance
the stability
of Mn
y
Sb
1
−
y
O
x
catalysts
in acidic
OER
conditions
while,
however,
producing
a reduction
in the OER
activity.
Despite
the continuous
corrosion
of both
Sb and Mn from
the as-
prepared
material,
the OER
overpotential
at
J
= 10 mA cm
−
2
did not substantially
increase,
even
at the point
that >90%
of
the catalyst
mass
had dissolved.
■
ASSOCIATED
CONTENT
*
sı
Supporting
Information
The
Supporting
Information
is available
free
of charge
at
https://pubs.acs.org/doi/10.1021/acsaem.4c00135.
Detailed
experimental
procedures,
materials
and chem-
icals,
sample
preparation,
electrochemical
measure-
ments,
materials
characterization,
additional
OER
over-
potential
data
and
metal
dissolution
rates,
scanning
electron
micrographs,
energy-dispersive
X-ray
spectros-
copy
data,
X-ray
diffraction
data,
and
X-ray
photo-
electron
spectra
(PDF)
■
AUTHOR
INFORMATION
Corresponding
Author
Nathan
S. Lewis
−
Division
of Chemistry
and Chemical
Engineering
and Beckman
Institute,
California
Institute
of
Technology,
Pasadena,
California
91125,
United
States;
orcid.org/0000-0001-5245-0538;
Email:
nslewis@
caltech.edu
Authors
Jacqueline
A. Dowling
−
Division
of Chemistry
and Chemical
Engineering,
California
Institute
of Technology,
Pasadena,
California
91125,
United
States;
orcid.org/0000-0001-
5642-8960
Zachary
P. Ifkovits
−
Division
of Chemistry
and Chemical
Engineering,
California
Institute
of Technology,
Pasadena,
California
91125,
United
States;
orcid.org/0000-0003-
2538-0794
Azhar I. Carim
−
Division
of Chemistry
and Chemical
Engineering
and Beckman
Institute,
California
Institute
of
Technology,
Pasadena,
California
91125,
United
States;
orcid.org/0000-0003-3630-6872
Jake M. Evans
−
Division
of Chemistry
and Chemical
Engineering,
California
Institute
of Technology,
Pasadena,
California
91125,
United
States;
orcid.org/0000-0002-
8721-5316
Madeleine
C. Swint
−
Division
of Chemistry
and Chemical
Engineering,
California
Institute
of Technology,
Pasadena,
California
91125,
United
States
Alexandre
Z. Ye
−
Division
of Chemistry
and Chemical
Engineering,
California
Institute
of Technology,
Pasadena,
California
91125,
United
States
Matthias
H. Richter
−
Division
of Engineering
and Applied
Sciences,
California
Institute
of Technology,
Pasadena,
California
91125,
United
States;
orcid.org/0000-0003-
0091-2045
Anna X. Li
−
Division
of Engineering
and Applied
Sciences,
California
Institute
of Technology,
Pasadena,
California
91125,
United
States;
orcid.org/0000-0002-3435-3651
Complete
contact
information
is available
at:
https://pubs.acs.org/10.1021/acsaem.4c00135
Figure
3.
Electrochemical
activity
and stability
of Mn
0.63
Sb
0.37
O
x
during
OER
at
J
= 100
mA
cm
−
2
in 1.0 M H
2
SO
4
(aq).
(A)
Chronopotentiometric
response.
(B) Cyclic
voltammograms
collected
initially
as well as after 24 h under
the galvanostatic
hold.
(C) Amount
of dissolved
metal
in the anolyte
as quantified
by ICP-MS,
presented
as a percentage
of the total
deposited
Sb and total
deposited
Mn.
ACS
Applied
Energy
Materials
www.acsaem.org
Letter
https://doi.org/10.1021/acsaem.4c00135
ACS Appl.
Energy
Mater.
2024,
7, 4288
−
4293
4291
Author
Contributions
⊥
J.A.D.
and Z.P.I.
contributed
equally.
Notes
The
authors
declare
the following
competing
financial
interest(s):
N.S.L.
is a scientific
founder
of and consultant
to
H2U
Technologies,
a company
developing
catalysts
and
electrolyzers
for the production
of hydrogen.
■
ACKNOWLEDGMENTS
This
work
was supported
by the U.S. Department
of Energy,
Office
of Science,
Office
of Basic
Science
under
Award
Number
DE-FG02-03-ER15483.
ICP-MS
data
were
collected
at the
Water
and
Environment
Lab
of the
Resnick
Sustainability
Institute
at the California
Institute
of Technol-
ogy.
XPS
data
were
collected
at the Molecular
Materials
Resource
Center
of the Beckman
Institute
at the California
Institute
of Technology.
■
REFERENCES
(1) Song,
J.; Wei,
C.; Huang,
Z.-F.;
Liu, C.; Zeng,
L.; Wang,
X.; Xu,
Z. J. A Review
on Fundamentals
for Designing
Oxygen
Evolution
Electrocatalysts.
Chem.
Soc. Rev.
2020
,
49
, 2196
−
2214.
(2) Ghavam,
S.; Vahdati,
M.; Wilson,
I. A. G.; Styring,
P. Sustainable
Ammonia
Production
Processes.
Front.
Energy
Res.
2021
,
DOI:
10.3389/fenrg.2021.580808.
(3) Nitopi,
S.; Bertheussen,
E.; Scott,
S. B.; Liu, X.; Engstfeld,
A. K.;
Horch,
S.; Seger,
B.; Stephens,
I. E. L.; Chan,
K.; Hahn,
C.; Nørskov,
J. K.; Jaramillo,
T. F.; Chorkendorff,
I. Progress
and Perspectives
of
Electrochemical
CO2
Reduction
on Copper
in Aqueous
Electrolyte.
Chem.
Rev.
2019
,
119
,
7610
−
7672.
(4) MIT
Energy
Initiative.
The Future
of Energy
Storage
;
Technical
Report;
Massachusetts
Institute
of Technology,
2022.
(5) Dowling,
J. A.; Rinaldi,
K. Z.; Ruggles,
T. H.; Davis,
S. J.; Yuan,
M.; Tong,
F.; Lewis,
N. S.; Caldeira,
K. Role
of Long-Duration
Energy
Storage
in Variable
Renewable
Electricity
Systems.
Joule
2020
,
4
,
1907
−
1928.
(6) Panchenko,
V. A.; Daus,
Yu. V.; Kovalev,
A. A.; Yudaev,
I. V.;
Litti,
Yu. V. Prospects
for the Production
of Green
Hydrogen:
Review
of Countries
with
High
Potential.
Int. J. Hydrog.
Energy
2023
,
48
,
4551
−
4571.
(7) Davis,
S. J.; Lewis,
N. S.; Shaner,
M.; Aggarwal,
S.; Arent,
D.;
Azevedo,
I. L.; Benson,
S. M.; Bradley,
T.; Brouwer,
J.; Chiang,
Y.-M.;
Clack,
C. T. M.; Cohen,
A.; Doig,
S.; Edmonds,
J.; Fennell,
P.; Field,
C. B.; Hannegan,
B.; Hodge,
B.-M.;
Hoffert,
M. I.; Ingersoll,
E.;
Jaramillo,
P.; Lackner,
K. S.; Mach,
K. J.; Mastrandrea,
M.; Ogden,
J.;
Peterson,
P. F.; Sanchez,
D. L.; Sperling,
D.; Stagner,
J.; Trancik,
J. E.;
Yang,
C.-J.;
Caldeira,
K. Net-Zero
Emissions
Energy
Systems.
Science
2018
,
360
,
eaas9793.
(8) Ayers,
K. The Potential
of Proton
Exchange
Membrane
−
Based
Electrolysis
Technology.
Curr. Opin. Electrochem.
2019
,
18
, 9
−
15.
(9) Buttler,
A.; Spliethoff,
H. Current
Status
of Water
Electrolysis
for
Energy
Storage,
Grid
Balancing
and Sector
Coupling
via Power-to-
Gas and Power-to-Liquids:
A Review.
Renew.
Sustain.
Energy
Rev.
2018
,
82
, 2440
−
2454.
(10)
Hubert,
M. A.; King,
L. A.; Jaramillo,
T. F. Evaluating
the Case
for Reduced
Precious
Metal
Catalysts
in Proton
Exchange
Membrane
Electrolyzers.
ACS Energy
Lett.
2022
,
7
, 17
−
23.
(11)
Riedmayer,
R.; Paren,
B. A.; Schofield,
L.; Shao-Horn,
Y.;
Mallapragada,
D. Proton
Exchange
Membrane
Electrolysis
Perform-
ance
Targets
for Achieving
2050
Expansion
Goals
Constrained
by
Iridium
Supply.
Energy
Fuels
2023
,
37
, 8614
−
8623.
(12)
Minke,
C.;
Suermann,
M.;
Bensmann,
B.; Hanke-
Rauschenbach,
R. Is Iridium
Demand
a Potential
Bottleneck
in the
Realization
of Large-Scale
PEM
Water
Electrolysis?
Int. J. Hydrog.
Energy
2021
,
46
, 23581
−
23590.
(13)
Bernt,
M.; Hartig-Weiß,
A.; Tovini,
M. F.; El-Sayed,
H. A.;
Schramm,
C.; Schröter,
J.; Gebauer,
C.; Gasteiger,
H. A. Current
Challenges
in Catalyst
Development
for PEM
Water
Electrolyzers.
Chem.
Ing. Technol.
2020
,
92
, 31
−
39.
(14)
Cherevko,
S.; Geiger,
S.; Kasian,
O.; Kulyk,
N.; Grote,
J.-P.;
Savan,
A.; Shrestha,
B. R.; Merzlikin,
S.; Breitbach,
B.; Ludwig,
A.;
Mayrhofer,
K. J. J. Oxygen
and Hydrogen
Evolution
Reactions
on Ru,
RuO
2
, Ir, and IrO
2
Thin
Film
Electrodes
in Acidic
and Alkaline
Electrolytes:
A Comparative
Study
on Activity
and Stability.
Catal.
Today
2016
,
262
,
170
−
180.
(15)
Ruggles,
T. H.; Dowling,
J. A.; Lewis,
N. S.; Caldeira,
K.
Opportunities
for Flexible
Electricity
Loads
Such
as Hydrogen
Production
from
Curtailed
Generation.
Adv. Appl. Energy
2021
,
3
,
No. 100051.
(16)
Han,
N.; Yang,
K. R.; Lu, Z.; Li, Y.; Xu, W.; Gao,
T.; Cai, Z.;
Zhang,
Y.; Batista,
V. S.; Liu, W.; Sun,
X. Nitrogen-Doped
Tungsten
Carbide
Nanoarray
as an Efficient
Bifunctional
Electrocatalyst
for
Water
Splitting
in Acid.
Nat. Commun.
2018
,
9
, 924.
(17)
Kwong,
W. L.; Lee, C. C.; Shchukarev,
A.; Messinger,
J. Cobalt-
Doped
Hematite
Thin
Films
for Electrocatalytic
Water
Oxidation
in
Highly
Acidic
Media.
Chem.
Commun.
2019
,
55
, 5017
−
5020.
(18)
Mondschein,
J. S.; Kumar,
K.; Holder,
C. F.; Seth,
K.; Kim,
H.;
Schaak,
R. E. Intermetallic
Ni
2
Ta Electrocatalyst
for the Oxygen
Evolution
Reaction
in Highly
Acidic
Electrolytes.
Inorg. Chem.
2018
,
57
, 6010
−
6015.
(19)
Pan,
S.; Li, H.; Liu, D.; Huang,
R.; Pan,
X.; Ren,
D.; Li, J.;
Shakouri,
M.; Zhang,
Q.; Wang,
M.; Wei,
C.; Mai,
L.; Zhang,
B.;
Zhao,
Y.; Wang,
Z.; Graetzel,
M.; Zhang,
X. Efficient
and Stable
Noble-Metal-Free
Catalyst
for Acidic
Water
Oxidation.
Nat. Commun.
2022
,
13
, 2294.
(20)
Ifkovits,
Z. P.; Evans,
J. M.; Kempler,
P. A.; Morla,
M. B.;
Pham,
K. H.; Dowling,
J. A.; Carim,
A. I.; Lewis,
N. S. Powdered
Mn
y
Sb
1
−
y
O
x
Catalysts
for Cerium-Mediated
Oxygen
Evolution
in
Acidic
Environments.
ACS Energy
Lett.
2022
,
7
, 4258
−
4264.
(21)
Moreno-Hernandez,
I. A.; MacFarland,
C. A.; Read,
C. G.;
Papadantonakis,
K. M.; Brunschwig,
B. S.; Lewis,
N. S. Crystalline
Nickel
Manganese
Antimonate
as a Stable
Water-Oxidation
Catalyst
in Aqueous
1.0 M H
2
SO
4
.
Energy
Environ.
Sci.
2017
,
10
, 2103
−
2108.
(22)
Evans,
T. A.; Choi,
K.-S.
Electrochemical
Synthesis
and
Investigation
of Stoichiometric,
Phase-Pure
CoSb
2
O
6
and MnSb
2
O
6
Electrodes
for the Oxygen
Evolution
Reaction
in Acidic
Media.
ACS
Appl. Energy
Mater.
2020
,
3
, 5563
−
5571.
(23)
Zhou,
L.; Shinde,
A.; Montoya,
J. H.; Singh,
A.; Gul, S.; Yano,
J.; Ye, Y.; Crumlin,
E. J.; Richter,
M. H.; Cooper,
J. K.; Stein,
H. S.;
Haber,
J. A.; Persson,
K. A.; Gregoire,
J. M. Rutile
Alloys
in the Mn
−
Sb
−
O
System
Stabilize
Mn
3+
To Enable
Oxygen
Evolution
in Strong
Acid.
ACS Catal.
2018
,
8
, 10938
−
10948.
(24)
Luke,
S.; Chatti,
M.; Yadav,
A.; Kerr,
B. V.; Kangsabanik,
J.;
Williams,
T.; Cherepanov,
P. V.; Johannessen,
B.; Tanksale,
A.;
MacFarlane,
D. R.; Hocking,
R. K.; Alam,
A.; Yella,
A.; Simonov,
A. N.
Mixed
Metal
−
Antimony
Oxide
Nanocomposites:
Low
pH Water
Oxidation
Electrocatalysts
with
Outstanding
Durability
at Ambient
and Elevated
Temperatures.
J. Mater.
Chem.
A
2021
,
9
, 27468
−
27484.
(25)
Shinde,
A.; Jones,
R. J. R.; Guevarra,
D.; Mitrovic,
S.; Becerra-
Stasiewicz,
N.; Haber,
J. A.; Jin, J.; Gregoire,
J. M. High-Throughput
Screening
for Acid-Stable
Oxygen
Evolution
Electrocatalysts
in the
(Mn
−
Co
−
Ta
−
Sb)O
x
Composition
Space.
Electrocatalysis
2015
,
6
,
229
−
236.
(26)
Laube,
A.; Hofer,
A.; Ressel,
S.; Chica,
A.; Bachmann,
J.;
Struckmann,
T. PEM
Water
Electrolysis
Cells
with
Catalyst
Coating
by Atomic
Layer
Deposition.
Int. J. Hydrog.
Energy
2021
,
46
, 38972
−
38982.
(27)
Mackus,
A. J. M.; Schneider,
J. R.; MacIsaac,
C.; Baker,
J. G.;
Bent,
S. F. Synthesis
of Doped,
Ternary,
and Quaternary
Materials
by
Atomic
Layer
Deposition:
A Review.
Chem.
Mater.
2019
,
31
, 1142
−
1183.
(28)
Yang,
R. B.; Bachmann,
J.; Reiche,
M.; Gerlach,
J. W.; Gösele,
U.; Nielsch,
K. Atomic
Layer
Deposition
of Antimony
Oxide
and
Antimony
Sulfide.
Chem.
Mater.
2009
,
21
, 2586
−
2588.
(29)
McCrory,
C. C. L.; Jung,
S.; Ferrer,
I. M.; Chatman,
S. M.;
Peters,
J. C.; Jaramillo,
T. F. Benchmarking
Hydrogen
Evolving
ACS
Applied
Energy
Materials
www.acsaem.org
Letter
https://doi.org/10.1021/acsaem.4c00135
ACS Appl.
Energy
Mater.
2024,
7, 4288
−
4293
4292
Reaction
and Oxygen
Evolving
Reaction
Electrocatalysts
for Solar
Water
Splitting
Devices.
J. Am. Chem.
Soc.
2015
,
137
,
4347
−
4357.
(30)
Dowling,
J. A. Long-Duration
Energy
Storage
in Reliable
Wind
and Solar
Electricity
Systems.
Ph.D.
Dissertation,
California
Institute
of Technology,
Pasadena,
CA, 2023.
ACS
Applied
Energy
Materials
www.acsaem.org
Letter
https://doi.org/10.1021/acsaem.4c00135
ACS Appl.
Energy
Mater.
2024,
7, 4288
−
4293
4293