A Janus Fe-SnO2 Catalyst that Enables Bifunctional Electrochemical Nitrogen Fixation

Article abstract of DOI:10.1002/anie.202003518

Electrochemical N₂ reduction reactions (NRR) and the N₂ oxidation reaction (NOR), using H₂O and N₂, are a sustainable approach to N₂ fixation. To date, owing to the chemical inertness of nitrogen, emerging electrocatalysts for the electrochemical NRR and NOR at room temperature and atmospheric pressure remain largely underexplored. Herein, a new-type Fe-SnO₂ was designed as a Janus electrocatalyst for achieving highly efficient NRR and NOR catalysis. A high NH₃ yield of 82.7 μg h^?1 mg_cat.^?1 and a Faraday efficiency (FE) of 20.4 percent were obtained for NRR. This catalyst can also serve as an excellent NOR electrocatalyst with a NO₃^? yields of 42.9 μg h^?1 mg_cat.^?1 and a FE of 0.84 percent. By means of experiments and DFT calculations, it is revealed that the oxygen vacancy-anchored single-atom Fe can effectively adsorb and activate chemical inert N₂ molecules, lowering the energy barrier for the vital breakage of N≡N and resulting in the enhanced N₂ fixation performance.

Full text of DOI:10.1002/anie.202003518

A Journal of the Gesellschaft Deutscher Chemiker
Angewandte
International Edition Chemie
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Accepted Article
Title: A Janus Fe-SnO2 Catalyst Enables Bifunctional Electrochemical
Nitrogen Fixation
Authors: Linlin Zhang, Meiyu Cong, Xin Ding, Yu Jin, Fanfan Xu, Yong
Wang, Lin Chen, and Lixue Zhang
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To be cited as: Angew. Chem. Int. Ed. 10.1002/anie.202003518
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COMMUNICATION
A Janus Fe-SnO Catalyst Enables Bifunctional Electrochemical
2
Nitrogen Fixation
[a]
[a]
[a,b]*
[b]
[a]
[c]
[d]
Linlin Zhang , Meiyu Cong , Xin Ding
, Yu Jin , Fanfan Xu ,Yong Wang , Lin Chen , Lixue
[a] *
Zhang
Dedication ((optional))
Abstract: Electrochemical N
2
reduction reactions (NRR) and N
O and N , represent a sustainable
fixation and arouse widespread attention. To date,
2
greenhouse
environmentally friendly alternative technique for N
therefore desirable from both energy and environment needs.
Advanced electrocatalysts for electrochemical reduction
reactions (NRR) and N oxidation reaction (NOR), represent a
sustainable approach to N fixation and arouse widespread
attention. An effective N fixation electrocatalyst should possess
sufficient active sites and in particular optimized electron
structure that can selectively absorb and activate the chemically
2 2
inert N and effectively suppress the side reactions during N
gas.
Developing
a
more
efficient and
oxidation reaction (NOR), using H
approach to N
2
2
2
fixation is
2
due to the chemical inertness of nitrogen, emerging electrocatalysts
for the electrochemical NRR and NOR at room temperature and
atmospheric pressure remain largely under explored. Herein, a new-
N
2
2
2
type Fe–SnO
2
was rationally designed as a Janus electrocatalyst for
yield
2
achieving highly efficient NRR and NOR catalysis. A high NH
3
−
1
−1
of 82.7 µg h mgcat. and a Faraday efficiency (FE) of 20.4 % were
obtained for NRR, superior than all noble-metal-free electrocatalysts
reported in acid electrolyte. This catalyst can also serve as an
fixation, i.e. hydrogen evolution reaction (HER) during NRR or
−
3
−1
9-23
excellent NOR electrocatalyst with a NO
yields of 42.9 µg h
oxygen evolution reaction (OER) during NOR.
−
1
mgcat. and a FE of 0.84%. By means of experiments and density
functional theory (DFT) calculations, we reveal that the oxygen
vacancy-anchored single-atom Fe can effectively adsorb and
Taking into account its thermal stability, acid resistance and
2
4-26
inactivity toward both HER and OER,
a promising catalyst candidate for N
reported SnO catalysts still showed the limited catalytic activity
for NRR mainly because they had relatively low conductivity,
SnO
2
was regarded as
2
fixation. Unfortunately, the
activate chemical inert N
2
molecules, lower the energy barrier for the
2
vital breakage of N≡N, resulting in the enhanced N
2
fixation
27,28
performance.
poor adsorption and weak activation for N
bypass these obstacles to N fixation by designing a new-type
Fe–SnO catalyst, inspired by the natural phenomenon that Fe,
as one of the cheapest and most abundant metals on the earth,
2
.
Herein, we
2
2
Nitrogen is indispensable in the biosynthesis of the basic
building-block molecules that sustain all forms of life, e.g., amino
29,30
exists in biological nitrogenases for natural N
2
fixation.
1, 2
acids and nucleotides that constitute DNA/RNA.
fixed-nitrogen compounds are NH and HNO , which are formed
in nature by biological nitrogenases and lightning. The worldwide
production of NH and HNO was 150 and 50 million metric tons,
respectively, in 2017. In industry, NH is synthesized by the
Haber–Bosch process, which involves reacting H and N at high
temperature (400–500 °C) and high pressure (20–30 MPa).
The commercial HNO was produced through the catalytic
oxidation of NH (Ostwald process), followed by a multistep
chemical reaction under harsh reaction conditions (15–25 MPa,
The usual
Different from the previously reported nanostructured Fe-based
3
3
31-37
NRR catalysts,
the Fe–SnO
2
catalyst presents a unique
can be
surface structure. The Fe elements in Fe–SnO
2
3
3
categorized into oxygen vacancy-anchored single-atom Fe and
lattice doped Fe, which are new strategies for enhancing the
3
2
2
adsorption and activation of N
electrical conductivity of SnO
activation abilities of Fe–SnO largely lowered the energy barrier
for the vital breakage of chemical inert N molecule. As a
consequence, the designed Fe–SnO catalyst exhibited
excellent bifunctional catalytic performance toward both NRR
2
2
on SnO and improving the
3
-5
2
, respectively. The out-bond
3
2
3
2
2
6
-8
400–600°C).
These processes are both energy intensive,
consuming tremendous global power and discharging global
−1
−1
and NOR: a high NH
3
yield of 82.7 µg h mgcat. and a Faraday
efficiency (FE) of 20.4% for the NRR, as the most active noble-
3
8-43
metal-free electrocatalysts in acid electrolyte,
and a high
yields of 42.9 µg h mgcat. and a FE of 0.84% for NOR in
.05 M H
This Fe–SnO simple
[a]
L. Zhang, M. Cong, X. Ding, F. Xu, L. Zhang
College of Chemistry and Chemical Engineering
Institution Qingdao University
−
−1
−1
NO
3
0
2
SO4.
Qingdao 266071, Shandong, PR China
E-mail: dingxin@qdu.edu.cn; zhanglx@qdu.edu.cn
X. Ding, Y. Jin
State Key Laboratory of Fine Chemicals, Dalian University of
Technology (DUT), Dalian 116024, Liaoning, PR China
Y. Wang
2
catalyst was prepared by
a
hydrothermal reaction (see details in Supporting Information).
Figure 1A shows that the X-ray diffraction (XRD) patterns of
[b]
[c]
[d]
SnO
peaks, at 26.61º, 33.89º, 37.95º, 51.78º, 57.81º, 65.91º, and
1.27º, corresponding to the (110), (101), (200), (211), (002),
301), and (202) planes, respectively, of SnO (JCPDS No. 41-
445). Neither iron oxide nor hydroxide was detected in the XRD
2
doped with different proportions of Fe displayed seven
Technische Universität München Department Chemie Lichtenbergstr.
7
4
D-85748 Garching Germany
(
2
L. Chen,
1
State Key Laboratory of Environment-friendly Energy Materials,
Southwest University of Science and Techaology, Mianyang 621010,
Sichuan PR China.
pattern. The chemical compositions and binding states of Fe–
SnO were investigated by X-ray photoelectron spectroscopy
2
Supporting information for this article is given via a link at the end of
the document. ((Please delete this text if not appropriate))
(XPS; Figure 1B and S1). The Sn 3d XPS spectra showed two
peaks, at 486.4 and 494.2 eV, which can be assigned to 3d5/2
and 3d3/2. A positive shift of the SnO
2
binding energy was
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observed in the Sn 3d XPS spectrum after Fe doping, indicative
SnO
2
. The Fe 3p spectra showed two peaks, at 56.4 and 59.7
for the reduced nature of oxygen vacancy on Fe-SnO
Doping with Fe was confirmed by the Fe 3p spectrum of Fe–
2
surface.
eV, corresponding to 3p3/2 and 3p1/2, respectively; and the peak
intensities increased with increasing dopant from 0% to 7%.
Scheme 1. (A) XRD patterns of catalysts, (B) XPS survey spectra of catalysts, (C) Fe K-edge XANES spectra of Fe–SnO
transforms of k3-weighted Fe K-edge of EXAFS spectra of Fe–SnO , Fe , and Fe foil; (E) HR-TEM image of Fe–SnO , (F) EDS elemental mapping images of
Fe, Sn, and O in Fe–SnO , (G) AFM image and corresponding line profiles, and (H) HAADF-STEM image of Fe–SnO
2 2 3
, Fe O , and Fe foil, (D) Fourier
2
O
2 3
2
2
2
Previously, the roles of oxygen vacancies in heteroatoms
doped transition metal oxides have been extensively discussed,
and the low-valance dopants have been shown to facilitate the
or clusters. Instead, Fe–SnO
2
gives
a first-shell Fe–O
contribution with a coordination number of about 3.6 at 2.01 Å,
and a first-shell Fe–Sn contribution with a coordination number
of about 0.4 at 3.12 Å, which can be assigned to lattice doped
44-46
formation of oxygen vacancies.
Herein, the oxygen vacancy
was studied with XPS and Electron paramagnetic resonance
Fe. The first-shell Fe–Sn contribution with
a coordination
(
5
EPR). The O 1s XPS patterns shows three main peaks at 529.9, number of about 4.4 at 3.87 Å can be assigned to Fe anchored
4
7-50
31.1, and 531.9 eV (Figure S2), which belong to the lattice
at oxygen vacancies, forming Sn-Fe-Sn structure.
Therefore,
oxygen, oxygen atoms in vicinity of oxygen vacancy and
the Fe elements in Fe–SnO can therefore be categorized into
isolated single-atom Fe confined distribution on surface with
oxygen vacancies and lattice doped Fe.
2
4
4
chemisorbed oxygen, respectively. The distinct EPR signals at
g = 2.004, from the electrons trapped in oxygen vacancy, show
that a large amount of oxygen vacancies generated on both
The morphologies and structures of nanosized Fe–SnO
2
SnO
2
and Fe-SnO
2
samples (Figure S3). Interestingly, the peak
catalyts were investigated by high-resolution transmission
electron microscopy (HR-TEM; Figure 1E) and atomic force
intensities in the O 1s XPS and EPR spectra clearly decreased
after Fe doping. These observations suggest the possible
formation of oxygen vacancy-anchored Fe. Similar to the
previous work by Wan et al, the oxygen vacancies formed on
microscopy (AFM; Figure 1G). Fe–SnO
characteristic spacing of 0.334 and 0.264 nm for the (110) and
(101) lattice planes, respectively. Energy-dispersive
spectroscopy (EDS) mapping showed that Fe, Sn, and O
elements were homogeneously distributed in Fe–SnO . The
AFM images showed two-dimensional Fe–SnO possessed a
2
shows two
ultrathin SnO
solution and anchor Fe atoms.
agreement with the positive shift in Sn 3d XPS spectra in Figure
(B). Then, the states of Fe element in Fe–SnO were further
identified by Fe K-edge X-ray absorption near-edge structure
XANES) spectroscopy. The XANES spectra of Fe–SnO
standard Fe (Fe–O), and Fe foil are shown in Figure 1C. The
near-edge of Fe–SnO is found to be between those of Fe foil
and Fe , suggesting that the average valence state of Fe is
2
can serve as “traps” to capture iron ion in acid
4
5-46
This deduction was also in
2
2
1
2
thickness ca.3 nm. Local defects were obtained after Fe doping
from the atomic arrangement in atomic-level high-angle annular
dark field-scanning TEM (HAADF-STEM) images (Figure 1H and
Figure S6)
(
2
,
2
O
3
2
2
The electrochemical N reduction was performed in an H-
2
O
3
type cell with pretreated 0.1 M HCl electrolyte. An Ag/AgCl
reference electrode was placed in the cathode chamber. The
counter electrode, which was in the anode chamber, was a
0
III
between Fe and Fe . The Fe chemical environment was then
probed by extended X-ray absorption fine structure (EXAFS)
spectroscopy (Figure 1 D, Figure S4-S5, and Table S1). The
EXAFS results show that there is no first-shell Fe–Fe
contribution for the Fe–SnO
major Fe species are not in the form of metallic Fe nanoparticles
graphite plate. Before the tests, the pretreated N
into the cathode chamber, rather than continuous flow of N
Protons were transported through the electrolyte and reacted
with N on the catalyst surface to produce NH . The NH yield
2
was bubbled
2
.
2
sample, which suggests that the
2
3
3
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was calculated by UV-vis absorption spectroscopy (Figure S7)
and ion chromatography (Figure S8-S9). The polarization curves
that the reaction on Fe–SnO
production. Stability tests showed minimal changes in the NH
2
gives excellent selectivity for NH
3
3
of Fe-SnO
2
(Fe3%-SnO
2
, if without special instructions) from LSV
yield (calculated from ion chromatograms and UV-vis absorption
spectra) over five reaction cycles (Figure S14-17). The FE
remained at ~20%, which indicates that Fe–SnO displays high
2
stability in the NRR. The stability could be further confirmed from
the long-time operation as shown in Figure S18. As shown in
measurements were shown in Figure 2A. The potential range
could be divided into NRR favorable region (ranging from -0.2 V
to -0.5 V vs RHE) and HER favorable region (lower than -0.5 V
2
vs RHE). In the NRR region, the current density in N saturated
electrolyte was much higher than that in Ar saturated electrolyte
for the contribution of NRR. The chronoamperometry curves for
Figure S19-21, comparison experiments show that the Fe-SnO
displays a much more enhanced NRR activity than commercially
available routine SnO and the vacancy-rich SnO (i.e. Fe0%
SnO ), which should be due to the unique Fe dopant as surface
defective active sites. The doping amount of Fe affected the
catalytic activity, and the maximum NH yield and FE were
obtained when the Fe ratio was 3% (Figure S22-25). Additionally,
the isotope labeling experiments were carried out in a simple
and economic pahtway as shown in supporting information, in a
2
Fe–SnO
shown in Figure 2B. The current density increased with the
potential. After 2 h of the electrocatalytic reaction, the NH yield
and FE obtained for the NRR reached maximum values at an
2
at various potentials in NRR favorable range are
2
2
-
2
3
3
−
1
applied potential of −0.3 V with a high NH
3
yield of 82.7 µg h
−
1
mgcat. and a high FE of 20.4% (Figure 2C and Figure S10-11),
which is superior than all noble-metal-free electrocatalysts
1
5
15
+
reported in acid electrolyte. The amount of N
was determined by the Watt−Chrisp method (Figure S12).
2
H
4
as a byproduct
N
2
-saturated electrolyte experiment, NH
double peak was detected (Figure 2D). These results suggest
that the detected NH was completely derived from the
4
with a specific
5
Figure S13 shows the UV-vis absorption spectra of the
3
−
electrolytes stained with p-C
9
H11NO indicator after NRR
electrochemical reduction of N
contaminants..
2
, rather than from NH
3
or NO
3
electrolysis at different potentials. The absence of N
2
H
4
indicates
Figure 2. (A) LSV curves for Fe–SnO
2
under Ar saturated and N
2
saturated electrolyte; (B) Dependence of current density on time for NRR with Fe–SnO
2
as
catalyst at various applied potentials(insert: the photograph of electrolyte treated using a indophenol blue method); (C) FEs and NH
3
production for NRR with Fe–
1
14
+
15
+
14
15
SnO
source; (E) LSV curves for Fe -SnO
catalyst at various applied potentials; (G) FE and NO
2
at various applied potentials; (D) H NMR spectra of both NH
4
and NH
4
produced from the NRR tests (at -0.3 V vs. RHE) using
N
2
or
N
2
as N
2
2
under Ar saturated and N
2
saturated electrolyte; (F) Dependence of current density on time for NOR with Fe–SnO
production for NOR with Fe–SnO at various applied potentials; (E) FEs and yield rates in Fe–SnO
produced from the NOR tests (at 1.96 V vs. RHE) using
2
as
−
3
2
2
cycling
14
-
3
15
-
3
14
15
tests; (H) MS spectra of both NO
and NO
2 2 2
N or N as N source.
Electrochemical NOR tests were performed in the same
electrolytic cell with pretreated 0.05 M H SO electrolyte. N
reacted with H O on the catalyst surface to produce NO
yield was calculated by ion chromatography (Figure S26-
7). The LSV polarization curves of Fe-SnO were shown in
Figure 3 E. The faradic range for NOR started from 1.6 V to 2.1
V vs RHE for Fe-SnO . As shown in the chronoamperometry
curves for Fe–SnO at various potentials (Figure 3F), the current
density increased with increasing potential from 1.76 to 2.16 V.
NOR at an applied potential of 1.96 V (Figure 2G, Figure S28).
−
2
4
2
Stability tests show minimal changes in the NO
reaction cycles and in the current density of long-time operation
(Figure S29-32), indicating that Fe–SnO has high stability in the
NOR. The results show that the maximum NO
3
yield over five
-
2
3
. The
−
NO
2
3
2
−
2
3
yield and FE
were also obtained at a Fe ratio of 3% (Figure S33-35). The
isotope labeling experiments were performed to verify that the
2
-
2
detected NO
3
was generated via the NOR process (Figure S36
15
and Figure 2H). In the
NO was obtained with a molecular weight of 62.9884,
compared with that of 61.988 for NO
N
2
-saturated electrolyte experiment,
−
15
-
After 2 h of the electrocatalytic reaction, a high NO
3
yield of
3
−
1
−1
14
-
14
42.9 µg h mgcat. and a high FE of 0.84% were obtained for
3
in the
2
N -saturated
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Angewandte Chemie International Edition
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COMMUNICATION
-
electrolyte. Additionally, no NO
3
was detected under open-
make all the NRR elementary steps downhill in terms of free
circuit conditions and in an Ar-saturated electrolyte after
energy on the pure SnO
determining potential decreases to about 0.803 V on Fe–
SnO (110). It indicates that the electrocatalytic activity of oxygen
vacancy-anchored Fe atom in the NRR is higher than that of the
surface under-coordinated Sn atom. The introduction of oxygen
vacancy-anchored Fe enables an alternative NRR mechanism
(Figure S38-39). For NOR, the most demanding step is the first-
2
(110) surface. However, the potential-
-
electrolysis for 2 h. These results suggest that the detected NO
was completely derived from the electrochemical oxidation of N
DFT simulations were performed to investigate the bonding
nature of the active centers and energetic pathways of N
reduction and oxidation over Fe-SnO (110) catalysts under
acidic conditions (Figure 3A-B, S37 and Table S2). As shown,
molecules interact weakly with the SnO (110) surface (ΔGN2
.337 eV), vacancy-rich SnO (110) surface (ΔGN2: 0.05 eV),
lattice doped Fe in Fe–SnO (ΔGN2: 0.41 eV for Fe site, -0.04 eV
for single/bi-Sn site) and the single/bi-Sn site in Fe–SnO with
3
2
.
2
2
2
N
2
2
:
step oxidation of N
free energy of 3.581 eV on SnO
SnO (110) (Figure 3E, 3F and S40-41). It suggests that the
introduction of oxygen vacancy-anchored Fe can increase the
electrocatalytic efficiency for both N reduction and oxidation.
The electronic structures of SnO and lattice Fe doped SnO
were also explored. Figure S42-S44 showed the calculated
density of states (DOS) of SnO , lattice Fe doped SnO and
oxygen vacancy-anchored Fe in Fe–SnO slab by DFT methods.
Compared with SnO , lattice Fe doped SnO exhibited a defect
2
to form NN(OH)*, which has an endothermic
0
2
2
(110) and 2.585 eV on Fe–
2
2
2
surface-anchored Fe (ΔGN2: 0.50 eV). The oxygen vacancy-
anchored Fe, which probably exists as protrusion-shaped
2
2
2
isolated active site, can effectively adsorb and activate N
molecules, as reflected by the favorable N adsorption free
2
2
2
2
energy (−0.49 eV) and an increased N≡N bond length (1.136 Å).
Therefore, the oxygen vacancy-anchored Fe should be the
2
2
2
active sites in Fe–SnO
proposed adjacent bi-Sn ion pairs.
The NRR kinetic pathway was then investigated based on the
calculated Gibbs free energy (ΔG) diagrams. Theoretically, the
associative distal pathway has been proved to be more
energetically preferable over an alternating pathway.
free-energy pathways (Figure 3C and 3D), the energetically
most difficult step, or potential-determining step, corresponds to
2
, rather than the single Sn or the newly
level below the conduction band, which effectively narrowed the
band gap and enhanced the electrical conductivity. It could also
be confirmed by the electrochemical impedance spectroscopy
(EIS) spectra in NRR (Figure S45). In the Nyquist plots, a
smaller charge transfer resistance (Rct) was obatined for Fe-
9,10,51
2
7,52
In the
SnO
2
under exact same conditions. Therefore, it is reasonable
act as the
that the oxygen vacancy-anchored Fe in Fe–SnO
2
active site and the lattice doped Fe answers for the improved
electrical conductivity, which are responsible for the enhanced
initial hydrogenation of adsorbed
2
N * to form an NNH*
intermediate. An onset potential of about 1.325 V is required to
2
N fixation performance together.
Figure 3. Stable adsorption configurations and corresponding adsorption energies for N
2
* on hydrogenated (110) surface of SnO
model; blue (N), gray (Sn), red (O), purple (Fe). (C) Free energy diagram of the NRR pathway along the alternating mechanism over the Sn site of
(110) surface in acid condition at U = 0 and U = -1.325 V, respectively; (D) Free energy diagram of the NRR pathway along the alternating mechanism
(110) in acid condition at U = 0 and U = -0.803 V, respectively. (E) Free-energy diagram for NOR under acidic conditions over the
(110) surface and (F) free-energy diagram for NOR under acidic condition over Fe-doped SnO (110) surface.
2
(A) and surface-anchored Fe
(B) in Fe–SnO
2
pure SnO
2
over the Fe site of Fe-SnO
SnO
2
2
2
−
−1
In summary, a new-type Fe–SnO
explored as an advanced electrocatalyst for ambient N
2
was synthesized and
fixation.
yield of 82.7 µg h mgcat. and a FE
0.4 % were obtained for NRR, superior than all the reported
3
catalyst in acid electrolyte. Besides, a NO yield of 42.9 µg h
−
1
2
mgcat. and a FE of 0.84% were also obtained for the Janus
catalyst in acid electrolyte. The outstanding activity was ascribed
to the improved adsorption and activation of N and improved
2
−
1
−1
A remarkable large NH
3
2
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Angewandte Chemie International Edition
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COMMUNICATION
electrical conductivity for the co-existence of the oxygen
vacancy-anchored Fe on SnO and the lattice doped Fe. DFT
2
calculations suggested the breakage of N≡N was the
energetically most difficult step for both NRR and NOR, the
oxygen vacancy-anchored single-atom Fe can effectively adsorb
[21] J. Li, S. Chen, F. Quan, G. Zhan, F. Jia, Z. Ai, L. Zhang Chem. 2020.
[
[
[
22] L. Xia, J. Yang, H. Wang, R. Zhao, H. Chen, W. Fang, A. M. Asiri, F. Xie,
G. Cui, X. Sun Chem. Commun. 2019, 55, 3371-3374.
23] C. Li, S. Mou, X. Zhu, F. Wang, Y. Wang, Y. Qiao, X. Shi, Y. Luo, B.
Zheng, Q. Li, X. Sun Chem. Commun. 2019, 55, 14474-14477
24] W. Luc, C. Collins, S. Wang, H. Xin, K. He, Y. Kang, F. Jiao J. Am. Chem.
Soc. 2017, 139, 1885-1893.
and activate chemical inert N
barrier, resulting in the enhanced N
2
molecules, lower the energy
fixation performance. This
2
[25] S. Liu, J. Xiao, X. F. Lu, J. Wang, X. Wang, X. W. D. Lou Angew Chem.
Int. Ed. 2019, 58, 8499-8503.
work offered a neoteric catalytic structure and provided brand
new ideas for the rational design of electrocatalysts for artificial
N fixation.
2
[26] D. Gao, Y. Zhang, Z. Zhou, F. Cai, X. Zhao, W. Huang, Y. Li, J. Zhu, P.
Liu, F. Yang, G. Wang, X. Bao J. Am. Chem. Soc. 2017, 139, 5652-
5655.
[
27] Y. P. Liu, Y. B. Li, H. Zhang, K. Chu Inorg. Chem. 2019, 58, 10424-10431.
28] L. Zhang, X. Ren, Y. Luo, X. Shi, A. M. Asiri, T. Li, X. Sun Chem.
Commun. 2018, 54, 12966-12969.
Acknowledgements ((optional))
[
This work was supported by the National Natural Science
Foundation of China (21908120 and 21875030), the Natural
Science Foundation of Shandong Province (ZR2018BB037), the
Youth Innovation Team Project of Shandong Provincial
Education Department (2019KJC023) and project of Qingdao
Applied Basic Research Programs of Science and Technology
[
29] Y. Chen, L. Liu, Y. Peng, P. Chen, Y. Luo, J. Qu J. Am. Chem. Soc. 2011,
133, 1147-1149.
[30] Y. Li, Y. Li, B. Wang, Y. Luo, D. Yang, P. Tong, J. Zhao, L. Luo, Y. Zhou,
S. Chen, F. Cheng, J. Qu Nat. Chem. 2013, 5, 320-326.
[
[
[
[
[
[
[
[
[
[
[
[
[
[
[
[
[
31] X. Zhu, Z. Liu, H. Wang, R. Zhao, H. Chen, T. Wang, F. Wang, Y. Luo, Y.
Wu, X. Sun Chem. Commun. 2019, 55, 3987-3990.
32] H. Huang, F. Li, Q. Xue, Y. Zhang, S. Yin, Y. Chen Small. 2019, 15,
(
18-2-2-10-jch and 18-2-2-35-jch)
1903500.
33] X. Cui, C. Tang, X. M. Liu, C. Wang, W. Ma, Q. Zhang Chemistry. 2018,
24, 18494-18501.
2
Keywords: N fixation • electrochemical nitrogen reduction •
34] Q. Liu, X. Zhang, B. Zhang, Y. Luo, G. Cui, F. Xie, X. Sun Nanoscale.
electrochemical nitrogen oxidation • bifunctional
2018, 10, 14386-14389.
35] Y. Li, Y. Kong, Y. Hou, B. Yang, Z. Li, L. Lei, Z. Wen ACS Sustain. Chem.
Eng. 2019, 7, 8853-8859.
[1] B. H. R. Suryanto, H.-L. Du, D. Wang, J. Chen, A. N. Simonov, D. R.
MacFarlane Nat. Catal. 2019, 2, 290-296.
36] X. Zhu, Z. Liu, Q. Liu, Y. Luo, X. Shi, A. M. Asiri, Y. Wu, X. Sun Chem.
Commun. 2018, 54, 11332-11335.
[
2] X. Cui, C. Tang, Q. Zhang Adv. Energy Mater. 2018, 8, 1800369.
3] Y. Zhu, L. Peng, Z. Fang, C. Yan, X. Zhang, G. Yu Adv. Mater. 2018, 30,
e1706347.
[
37] X. Zhao, X. Lan, D. Yu, H. Fu, Z. Liu, T. Mu Chem. Commun. 2018, 54,
13010-13013.
[
4] Y. C. Wan, J. C. Xu, R. T. Lv Mater. Today. 2019, 27, 69-90.
5] X. Zhu, T. Wu, L. Ji, C. Li, T. Wang, S. Wen, S. Gao, X. Shi, Y. Luo, Q.
Peng, X. Sun J. Mater. Chem. A. 2019, 7, 16117-16121.
6] M. Cheng, C. Xiao, Y. Xie J. Mater. Chem. A. 2019, 7, 19616-19633.
7] Y. Wang, Y. Yu, R. Jia, C. Zhang, B. Zhang Natl. Sci. Rev. 2019, 6, 730-
38] L. Xia, J. Yang, H. Wang, R. Zhao, H. Chen, W. Fang, A. M. Asiri, F. Xie,
G. Cui, X. Sun Chem. Commun. 2019, 55, 3371-3374.
[
39] X. Liu, H. Jang, P. Li, J. Wang, Q. Qin, M. G. Kim, G. Li, J. Cho Angew
Chem. Int. Ed. . 2019, 58, 13329-13334.
[
[
40] X. Qu, L. Shen, Y. Mao, J. Lin, Y. Li, G. Li, Y. Zhang, Y. Jiang, S. Sun
ACS Appl. Mater. Inter. 2019, 11, 31869-31877.
738.
[
[
[
[
[
[
8] Y. Liu, M. Cheng, Z. He, B. Gu, C. Xiao, T. Zhou, Z. Guo, J. Liu, H. He, B.
Ye, B. Pan, Y. Xie Angew Chem. Int. Ed. 2019, 58, 731-735.
9] N. Cao, Z. Chen, K. Zang, J. Xu, J. Zhong, J. Luo, X. Xu, G. Zheng Nat.
Commun. 2019, 10, 2877.
41] W. Qiu, X. Y. Xie, J. Qiu, W. H. Fang, R. Liang, X. Ren, X. Ji, G. Cui, A. M.
Asiri, G. Cui, B. Tang, X. Sun Nat. Commun. 2018, 9, 3485.
42] C. Lv, Y. Qian, C. Yan, Y. Ding, Y. Liu, G. Chen, G. Yu Angew Chem. Int.
Ed. 2018, 57, 10246-10250.
10] R. Shi, Y. X. Zhao, G. I. N. Waterhouse, S. Zhang, T. R. Zhang Acs Catal.
43] F. Xu, L. Zhang, X. Ding, M. Cong, Y. Jin, L. Chen, Y. Gao Chem.
Commun. 2019, 55, 14111-14114
2019, 9, 9739-9750
11] L. Xia, B. Li, Y. Zhang, R. Zhang, L. Ji, H. Chen, G. Cui, H. Zheng, X. Sun,
F. Xie, Q. Liu Inorg. Chem. 2019, 58, 2257-2260.
44] C. D. Lv, C. S. Yan, G. Chen, Y. Ding, J. X. Sun, Y. S. Zhou, G. H. Yu
Angew Chem Inte. Ed. 2018, 57, 6073-6076.
12] M. Wang, S. Liu, T. Qian, J. Liu, J. Zhou, H. Ji, J. Xiong, J. Zhong, C. Yan
Nat. Commun. 2019, 10, 341.
45] Y. Chen, S. Ji, C. Chen, Q. Peng, D. Wang, Y. Li Joule. 2018, 2, 1242-
1264.
13] H. Tao, C. Choi, L.-X. Ding, Z. Jiang, Z. Han, M. Jia, Q. Fan, Y. Gao, H.
Wang, A. W. Robertson, S. Hong, Y. Jung, S. Liu, Z. Sun Chem. 2019,
46] J. Wan, W. Chen, C. Jia, L. Zheng, J. Dong, X. Zheng, Y. Wang, W. Yan,
C. Chen, Q. Peng, D. Wang, Y. Li Adv. Mater. 2018, 30.
5, 204-214.
47] H. Li, S. Wang, H. Sawada, G. G. Han, T. Samuels, C. S. Allen, A. I.
Kirkland, J. C. Grossman, J. H. Warner ACS Nano. 2017, 11, 3392-
[
[
[
[
[
[
[
14] L. Xia, X. Wu, Y. Wang, Z. Niu, Q. Liu, T. Li, X. Shi, A. M. Asiri, X. Sun
Small Methods. 2018, 3, 1800251.
3403.
15] H. Cheng, L. X. Ding, G. F. Chen, L. Zhang, J. Xue, H. Wang Adv. Mater.
[
48] S. Zhang, P. N. Plessow, J. J. Willis, S. Dai, M. Xu, G. W. Graham, M.
Cargnello, F. Abild-Pedersen, X. Pan Nano Lett. 2016, 16, 4528-4534.
49] G. Liu, A. W. Robertson, M. M. Li, W. C. H. Kuo, M. T. Darby, M. H.
Muhieddine, Y. C. Lin, K. Suenaga, M. Stamatakis, J. H. Warner, S. C.
E. Tsang Nat. Chem. 2017, 9, 810-816.
2018, 30, 1803694.
16] T. Wu, X. Zhu, Z. Xing, S. Mou, C. Li, Y. Qiao, Q. Liu, Y. Luo, X. Shi, Y.
Zhang, X. Sun Angew Chem Int. Ed. 2019, 58, 18449-18453.
17] C. Li, J. Yu, L. Yang, J. Zhao, W. Kong, T. Wang, A. M. Asiri, Q. Li, X. Sun
Inorg. Chem. 2019, 58, 9597-9601..
[
[
[
[
50] A. Sasahara, C. L. Pang, H. Onishi J. Phys. Chem. B. 2006, 110, 13453-
18] Y. Li, Q. Zhang, C. Li, H.-N. Fan, W.-B. Luo, H.-K. Liu, S.-X. Dou J. Mater.
Chem. A. 2019, 7, 22242-22247.
13457.
51] Y. Tong, H. Guo, D. Liu, X. Yan, P. Su, J. Liang, S. Zhou, J. Liu, G. Q. M.
Lu, S. X. Dou Angew Chem. Int. Ed. 2020. 10.1002/anie.202002029
52] T. Wu, W. Kong, Y. Zhang, Z. Xing, J. Zhao, T. Wang, X. Shi, Y. Luo, X.
Sun Small Methods. 2019, 3, 1900356.
19] X. Zhu, T. Wu, L. Ji, C. Li, T. Wang, S. Wen, S. Gao, X. Shi, Y. Luo, Q.
Peng, X. Sun J. Mater. Chem. A. 2019, 7, 16117-16121.
20] J. Wang, B. Huang, Y. Ji, M. Sun, T. Wu, R. Yin, X. Zhu, Y. Li, Q. Shao, X.
Huang Adv. Mater. 2020, e1907112.
This article is protected by copyright. All rights reserved.

Angewandte Chemie International Edition
10.1002/anie.202003518
COMMUNICATION
COMMUNICATION
A new-type Fe–SnO
and explored
electrocatalyst for both NRR and NOR
firstly. The Fe elements in Fe–SnO
2
was synthesized
Linlin Zhang, Meiyu Cong, Xin Ding*,
Yu Jin, Yong Wang, Fanfan Xu, Lin
Chen, Lixue Zhang*
as Janus
a
2
can be categorized into oxygen
vacancy anchored Fe and lattice
doped Fe, which enhances the
Page No. 1– Page No.5
2
A Janus Fe-SnO Catalyst Enables
Bifunctional Electrochemical
Nitrogen Fixation
adsorption and activation of N
SnO and improves the electrical
conductivity of SnO , respectively. As
2
on
2
2
a consequence, the catalyst exhibited
excellent catalytic performance toward
both NRR and NOR: a high NH
3
yield
−
1
−1
of 82.7 µg h mgcat. and a FE of
−
2
0.4% and a high NO
3
yields of 42.9
−
1
−1
µg h mgcat. and a FE of 0.84% .
This article is protected by copyright. All rights reserved.