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(1) Haber-Bosch Process N2 and H2 reacting at 15–25 MPa and between 400–500°C Energy and capital intensive approach
High Rate Ammonia Synthesis by Intermediate Temperature Solid-state Alkaline Electrolyzer Storagenergy Technologies Inc.: Feng Zhao, Jared Liao and Byron Millet
Subcontractors: Iowa State University: Wenzhen Li, Yifu Chen; Pennsylvania State University: Michael Janik, Yawei Lee
Technical & Business Contact: Feng Zhao, 801-386-8555, [email protected]
Introduction
Our Approach
(2) Electrochemical synthesis Low temperature, pressure, energy input, and emissions Enables networks of distributed scale and near point-of-use
Issues of Current Electrochemical Synthesis Methods
Only molten salt system operating at intermediate temperature range Low ammonia production rate due to lack of highly active NRR catalyst Low selectivity of nitrogen reduction due to HER Poor stability using liquid based and proton-conducting electrolyte
Ammonia Synthesis Methods
We will develop a game-changing intermediate temperature (100-300oC)solid-state alkaline electrolyzer (ITSAE) for high-rate ammonia productionfrom nitrogen/air and steam electrolysis based on following innovations:
(1) Cost-effective and intermediate temperature highly OH- conductingsolid membrane
Final TargetsPeriods/Parameters Phase I (Completed) Phase II (Two Years) Phase IIS (One Year)
Cell/Stack 5-cm2 single cell 5-cm2 single cell Stack
Membrane conductivity (mS/cm) >40 >100 >100
Membrane thickness (µm) ≤300 ≤50 ≤50
Current density (mA/cm2) 5.0 350 300
Coulombic Efficiency (%) ≥20 ≥94 ≥90
Ammonia production rate (mol/cm2/s) ≥3.5x10-9 ≥1.1x10-6 ≥9.4.0x10-7
Energy Efficiency (%) - >65 >60
Membrane
Acknowledgement: This project is supported by DOE ARPA-E REFUEL program (REFUEL-DE-AR0000818). We thank Drs. Grigorii Soloveichik, Julian Sculley, and Madhav Acharya.
Work Plan
Develop large ITSA membrane with thickness of ≤50 µm and ASR of ≤0.125 Ω cm2
Develop highly active and selective Fe based bimetallic oxide NRR cathode Use DFT methods to elucidate elementary reaction mechanisms and guide
catalyst design Optimize MEA and ITSAE operation conditions Demonstrate ITSAE stack with productivity of 100 g/day Techno-economic- analysis and Technology to Market
Nanosized MTP (M=Sb, Mo, V, W) powder was synthesized with high purity (except VTP). The synthesized MoTP materials exhibits highest conductivity of 87 mS/cm at 150oC. Large MoTP/PTFE composite membrane was fabricated with thickness of < 300 mm The ASR of MoTP/PTFE membrane is around 0.52 Ω cm2
NRR Catalyst
DFT calculation shows that Ni dopant facilitate N2RR in a robust way Partially reduced NiFeOx@RTO nanoparticles were fabricated as NRR catalyst ITSAE exhibited a Coulombic Efficiency of 4.54% and ammonia production rate of 3.14 X 10-9 mol/cm2/s at 150oC using
85%N2+15% H2O.
Technology to Market(1) The cost of ammonia produced by 150 MW ITSAE plant is around 0.1133$/kWh. which is 10% lower than REFUEL target
($0.128/kWh).(2) Main cost factors have been identified as electrode cost, ITSAE energy efficiency, and electricity cost.(3) Distributed ammonia production systems with productivity of 1 and 10 ton/day were selected for the first market
application.
20 30 40 50 60 70
SnP2O
7 JCPDS 29-1352
? SnO2
?
ATP
WTP
MTP
Inte
ns
ity
/ a
.u.
2 (Degree)
VTP?
0
5
10
15
20
25
30
20 mA cm-2
10 mA cm-2
5 mA cm-2
Fa
rad
aic
Eff
icie
nc
y /
%
1 mA cm-2
0.0
1.0x10-9
2.0x10-9
3.0x10-9
4.0x10-9
5.0x10-9
Ra
te /
mo
l NH
3 c
m-2 s
-1
re-NiFe/RTO, 150oC, ambient P, 15% water
TiO2
NiFe (amorphous)
Ru,Fe or Ru4Fe
MoTP/PTFE membrane
20 30 40 50 60 70 80 90
reduced NiFeOx/RTO
NiFeOx/RTO
Ru 06-0663
% %
*
%%
%
%%
Fe 06-0696
Ru4Fe 40-1147
%
&
&
^
^
^
^
^
^
***
*
*++
+
#
#
#
Inte
nsity (
arb
. unit)
2theta (o)
RuO2 43-1027#
+ Rutile TiO2 21-1276
* Anatase TiO2 21-1272
^
&
297 294 291 288 285 282 279 276
Ru4+
Ru 3d5/2
ox-NiFeOx@RTO
re-NiFeOx@RTO
Inte
ns
ity / a
.u.
Binding energy / eV
NiFeOx@RTO
C 1s
Ru0
735 730 725 720 715 710 705 700
Fe0
Fe3+
Fe 2p
Inte
ns
ity
/ a
.u.
Binding energy / eV
ox-NiFeOx@RTO
re-NiFeOx@RTO
NiFeOx@RTO
890 885 880 875 870 865 860 855 850 845
Ni 2p
Ni0
Ni2+
Inte
ns
ity / a
.u.
Binding energy / eV
NiFeOx@RTO
re-NiFeOx@RTO
Dopant Effect on Fe2O3(0001)
Ni doping
W/O doping
(2) Nanostructured Fe2O3-based bimetal oxide nitrogen reduction reaction (NRR) cathode catalyst
(3) Advanced solid composite electrode structure
(4) Noble metal-free oxygen evolution reaction (OER) anode catalyst
ASR = 0.52 Ω cm2