1
1
Supporting Information
2
Non-precious triple-atom catalysts with ultra-high activity for
3
electrochemical reduction of nitrate to ammonia: a DFT screening
4
Xiangyi Zhou
1†
, Mohsen Tamtaji
2†
, Weijun Zhou
3
, William A. Goddard III
4
*,
5
GuanHua Chen
1,2
*
6
1
Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong
7
Kong SAR, 999077, China
8
2
Hong Kong Quantum AI Lab Limited, Pak Shek Kok, Hong Kong SAR, 999077,
9
China
10
3
QuantumFabless Limited, Pak Shek Kok, Hong Kong SAR, 999077, China
11
4
Materials and Process Simulation Center (MSC), MC 139-74, California Institute
12
of Technology, Pasadena CA, 91125, USA
13
†These authors contributed equally to this work.
14
*Corresponding Authors, email:
ghc@everest.hku.hk, and
wag@caltech.edu
15
ORCID: XYZ: 0009-0002-8311-0768; MT: 0000-0001-9118-5474; WJZ: 0000-
16
0002-4328-3704; WAG: 0000-0003-0097-5716; GHC: 0000-0001-5015-0902
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2
1
Note S1. Elementary steps in NO
3
RR
2
The observed processes in this work during the search of minimum energy reaction
3
pathways of NO
3
RR (Fig. 3c in main text) are presented here:
Proton 0:
*
+
NO
3
̄
→
*NO
3
+ e
−
(S1)
Proton 1: *NO
3
+ (H
+
+ e
−
)
→
*NO
2
+
∗
OH
(S2)
Proton 2: *NO
2
+
∗
OH + (H
+
+ e
−
)
→
*NO + 2
∗
OH
(S3)
Proton 2: *NO
2
+
∗
OH + (H
+
+ e
−
)
→
*NO +
∗
O + H
2
O
(S4)
Proton 2: *NO
2
+
∗
OH + (H
+
+ e
−
)
→
*NO
2
+ H
2
O
(S5)
Proton 3: *NO + 2
∗
OH + (H
+
+ e
−
)
→
*NO +
∗
OH + H
2
O
(S6)
Proton 3: *NO +
∗
O + (H
+
+ e
−
)
→
*NO +
∗
OH
(S7)
Proton 3: *NO
2
+ (H
+
+ e
−
)
→*NO
+
∗
OH
(S8)
Proton 4: *NO +
∗
OH + (H
+
+ e
−
)
→
*NO + H
2
O
(S9)
Proton 5: *NO + (H
+
+ e
−
)
→*N
+
∗
OH
(S10)
Proton 6: *N +
∗
OH + (H
+
+ e
−
)
→
*N + H
2
O
(S11)
Proton 6: *N +
∗
OH + (H
+
+ e
−
)
→
*NH +
∗
OH
(S12)
Proton 7: *N + (H
+
+ e
−
)
→
*NH
(S13)
Proton 7: *NH +
∗
OH + (H
+
+ e
−
)
→
*NH
2
+
∗
OH
(S14)
Proton 8: *NH + (H
+
+ e
−
)
→
*NH
2
(S15)
Proton 8: *NH
2
+
∗
OH + (H
+
+ e
−
)
→
*NH
3
+
∗
OH
(S16)
Proton 9: *NH
2
+ (H
+
+ e
−
)
→
*NH
3
(S17)
Proton 9: *NH
2
+
∗
OH + (H
+
+ e
−
)
→
*NH
3
(S18)
4
5
3
1
2
3
Figure S1.
Schematics of (a-b) two kinds of substrates for bimetallic M
2
M′-
4
TACs and (c) the energy difference between the two kinds. The energy difference is
5
defined as
E
(substrate-2) -
E
(substrate-1). Substrate-2 (the secondary metal atom
M′
at
6
M#3) is energetically preferable for all studied bimetallic TACs.
7
8
9
Figure S2.
The reaction pathway (a) and the optimized configurations of
10
intermediates (b) of NO
3
RR for Rh
3
-TAC.
4
1
2
Figure S3.
The reaction pathway (a) and the optimized configurations of
3
intermediates (b) of NO
3
RR for Co
3
-TAC without considering the influence of multiple
4
nitrate adsorptions and pre-adsorption of H
2
O in the working environment.
5
6
7
Figure S4.
The reaction pathway (a) and the optimized configurations of
8
intermediates (b) of NO
3
RR for Cu
3
-TAC.
9
5
1
2
Figure S5.
The reaction pathway (a) and the optimized configurations of
3
intermediates (b) of NO
3
RR for Pd
3
-TAC.
4
5
6
Figure S6.
The reaction pathway (a) and the optimized configurations of
7
intermediates (b) of NO
3
RR for Fe
3
-TAC.
8
6
1
2
Figure S7.
The reaction pathway (a) and the optimized configurations of
3
intermediates (b) of NO
3
RR for Fe
2
Ni-TAC.
4
5
6
Figure S8.
The adsorption free energies of intermediates in six protonation steps
7
(step 0, step 1, step 3, step 4, step 5, and step 9) against limiting potential.
8
9
10
7
1
Table S1.
Computed formation energies (
E
form
) and dissolution potential (
U
diss
)
2
of homonuclear M
3
-TACs.
E
M
is the atomic energy of metal M in its bulk phase.
3
U
o
diss_M
is the standard dissolution potential of the metal M.[1]
n
is the number of
4
electrons transferred during the dissolution.[2] The energy of the nitrogen-doped
5
graphene substrate
E
NG
is -395.72 eV. The unit of all energies is eV, and the unit of all
6
potential is V.
TACs
E
M
E
form
U
o
diss_M
n
U
diss
Sc
3
-6.25
-3.58
-2.08
3
-0.89
Ti
3
-7.84
-2.58
-1.63
2
-0.34
V
3
-8.99
-1.23
-1.18
2
-0.57
Cr
3
-9.51
-0.96
-0.91
2
-0.43
Mn
3
-9.01
-1.30
-1.19
2
-0.54
Fe
3
-8.24
-1.12
-0.45
2
0.11
Co
3
-7.02
-1.03
-0.28
2
0.23
Ni
3
-5.47
-1.39
-0.26
2
0.43
Cu
3
-3.73
-0.99
0.34
2
0.83
Zn
3
-1.11
-1.21
-0.76
2
-0.16
Y
3
-6.43
-3.59
-2.37
3
-1.17
Zr
3
-8.52
-2.35
-1.45
4
-0.86
Nb
3
-10.22
-0.74
-1.10
3
-0.85
Mo
3
-10.93
-0.20
-0.20
3
-0.13
Ru
3
-9.23
-0.03
0.46
2
0.48
Rh
3
-7.26
-0.39
0.60
2
0.79
Pd
3
-5.22
-0.64
0.95
2
1.27
Ag
3
-2.72
0.00
0.80
1
0.80
Cd
3
-0.75
-0.49
-0.40
2
-0.16
Hf
3
-9.93
-2.00
-1.55
4
-1.05
Ta
3
-11.81
-0.48
-0.60
3
-0.44
W
3
-12.95
0.34
0.10
3
-0.01
Re
3
-12.43
0.33
0.30
3
0.19
Os
3
-11.25
0.45
0.84
8
0.78
Ir
3
-8.85
-0.04
1.16
3
1.17
Pt
3
-6.10
-0.67
1.18
2
1.51
Au
3
-3.22
0.06
1.50
3
1.48
7
8
8
1
Table S2.
Computed formation energies (
E
form
) and dissolution potential (
U
diss
)
2
of bimetallic M
2
M′-TACs.
E
M′
and
E
M
are the atomic energies of metals
M′
and M in
3
their bulk phase, respectively. The number of electrons transferred during the
4
dissolution (
n
) is 2 for four metals involved in studied bimetallic TACs.[2]
U
o
diss_
M'
5
and
U
o
diss_M
are the standard dissolution potential of the metals
M′
and M,
6
respectively.[1]
U
diss
is taken as the minimum of
U
diss_M′
and
U
diss_M
. The energy of the
7
nitrogen-doped graphene substrate
E
NG
is -395.72 eV. The unit of all energies is eV,
8
and the unit of all potential is V.
TACs
E
M
E
M′
E
form
U
o
diss_M
U
o
diss_
M'
U
diss_M
U
diss_M′
U
diss
Co
2
Fe
-7.02
-8.24
-1.18
-0.28
-0.45
0.31
0.14
0.14
Co
2
Ni
-7.02
-5.47
-1.17
-0.28
-0.26
0.31
0.33
0.31
Co
2
Cu
-7.02
-3.73
-1.22
-0.28
0.34
0.33
0.95
0.33
Fe
2
Ni
-8.24
-5.47
-1.26
-0.45
-0.26
0.18
0.37
0.18
9
10
9
1
Table S3.
The most stable configuration of adsorbed *NO
3
, and the adsorption
2
free energy of on TACs
TACs
Adsorption configuration
Δ
G
*NO3
(eV)
Fe
3
(3)
-0.75
Co
3
(1)
-0.12
Ni
3
(3)
0.19
Cu
3
(1)
-0.23
Rh
3
(3)
-0.87
Pd
3
(3)
0.09
Pt
3
(3)
0.66
Co
2
Fe
(1)
-0.58
Co
2
Ni
(1)
-0.15
Co
2
Cu
(2)
-0.10
Fe
2
Ni
(3)
-0.29
3
4
Table S4.
The limiting potential (
U
L
) and d band center
(ε
d
) on Fe
3
, Ni
3
, Cu
3
-
5
TACs.
TACs
U
L
(V)
ε
d
(eV)
Fe
3
-1.16
-0.52
Ni
3
-0.31
-1.48
Cu
3
-0.66
-3.04
6
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