Supporting information for between graphitization …Freeze-drying was used to remove solvent while retaining the porous structure of the PANI hydrogel composite. The resulting solid
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Supporting information for
3D Porous Graphitic Nanocarbon for Enhancing Durability of Pt Catalysts: Balance
between graphitization and hierarchical porosity
Zhi Qiaoa,1, Sooyeon Hwangb,1, Xing Lib,h,1, Chenyu Wangc,1, Widitha Samarakoond, Stavros Karakalose, Dongguo Lic, Mengjie Chena, Yanghua Hea, Maoyu Wangd, Zhenyu Liug, Guofeng Wangg, Hua Zhouf, Zhenxing Feng *d, Dong Su*b, Jacob S. Spendelow*c and Gang Wu*a
a, Department of Chemical and Biological Engineering, University at Buffalo, The State University
of New York, Buffalo, New York 14260, United Statesb, Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York
11973, United Statesc, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos,
New Mexico 87545, United Statesd, School of Chemical, Biological, and Environmental Engineering, Oregon State University,
Corvallis, Oregon 97333, United Statese, Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina
29208, United States
f X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, United Statesg, Department of Mechanical Engineering and Materials Science, University of Pittsburgh,
Pittsburgh, PA 15261, United Statesh, Department of Physics and Engineering, Key Laboratory of Material Physics, Zhengzhou
Figure S15. Optimized atomistic structures (top panel: top view; bottom panel: side view) and
predicted binding energy of a single Pt atom adsorbed on an un-doped graphene layer on the top
of (a) the center of a carbon ring, (b) a carbon atom, and (c) the middle point of two neighboring
carbon atoms. In the figure, the gray and cyan balls represent carbon and platinum atoms,
respectively.
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Figure S16. Optimized atomistic structures (top panel: top view; bottom panel: side view) and
predicted binding energy of a single Pt atom adsorbed on an N-doped graphene layer on the top of
(a) the doped graphitic N atom, (b) a carbon atom far-away from the doped graphitic N atom, (c)
a carbon atom adjacent to the doped graphitic N atom, and (d) the middle point of two neighboring
carbon atoms adjacent to the doped graphitic N atom. In the figure, the gray, cyan, and blue balls
represent carbon, platinum, and nitrogen atoms, respectively.
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Figure S17. Optimized atomistic structures (top panel: top view; bottom panel: side view) of a
thirteen-Pt-atom cluster adsorbed on (a) an un-doped graphene layer and (b) an N-doped graphene
layer. In the figure, the gray, cyan, and blue balls represent carbon, platinum, and nitrogen atoms,
respectively.
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Figure S18. (a) Charge density difference of N-doped graphene layer with respect to the
superposition of atomic charge density; Charge density difference of Pt cluster adsorbed (b) on an
undoped graphene layer and (c) on an N-doped graphene layer with respect to the superposition of
the charge density of Pt cluster and graphene layer. The magenta and yellow region refers to the
increase and decrease in charge density, respectively. The isosurface level is set to be 0.015 e Å-3
in (a) and 0.007 e Å-3 in (b) and (c). In the figure, the gray, cyan, and blue balls represent carbon,
platinum, and nitrogen atoms, respectively.
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Figure S19. ORR steady-state polarization plots (0.1 M HClO4, 900rpm) during high potential
ASTs for Pt catalysts supported by different PGCs derived from various temperature.
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Figure S20. ORR steady-state polarization plots (0.1 M HClO4, 900 rpm) during high potential
ASTs for Pt catalysts supported by different hydrogel-based carbon derived from various metals.
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Figure S21. ORR steady-state polarization plots (0.1 M HClO4, 900rpm) during even higher
potential ASTs (1.0 – 1.6 V) for different Pt catalysts.
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Figure S22. ORR polarization (0.1 M HClO4, 900rpm) and CV plots for Pt/Mn-PANI-PPy-PGC
with and without post treatment; and the comparison of their stabilities.
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Figure S23. TEM and STEM-EDS images of Pt/Mn-PANI-PPy-PGC without post heat treatment
and the corresponding particle size distribution.
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Figure S24. N2 adsorption/desorption plots and corresponding pore size distributions for different
Pt/C compared with Pt/PGC.
Table S4. Average particles size of Pt and their ECSA for different Pt/C catalysts.
Pt/C
Properties
Pt/PGCPt/PGC
(Without post
treatment)
TEC10V20E TEC10EA20E TEC10E20E
Average Pt particles size-
nm5.61 3.83 3.4[6] 3.87[7] 2.94[7]
ECSA-m2/g
(Hupd analysis)67.2 74.6 55.1 38.4 83.7
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Figure S25. Raman spectra for different Pt/C compared with Pt/PGC.
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Figure S26. RDE potential cycling stability tests for Pt/Mn-PANI-PPy-PGC, TEC10V20E and
TEC10EA20E during low potential range (0.6-1.0V).
(a)
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(b)
(c)
(d)
(e) (b)
)
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Figure S27. Stability tests results for different Pt/C and Pt/PGC, and their corresponding CV plots
and change of ECSA.
(f) (b)
)
(g)
(h)
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Figure S28. Comparison of the morphology and microstructure among (a) original Pt/Mn-PANI-
PPy-PGC, and the ones after RDE potential cycling stability tests during (b) high potential range
and (c) low potential range.
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Figure S29. The corresponding Pt particle size distribution of (a) Pt/Mn-PANI-PPy-PGC and the
ones after (b) high potential ASTs and (c) low potential ASTs, according to the TEM images in
Figure S28.
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Figure S30. ORR steady-state polarization plots (0.1 M HClO4, 900rpm) during high potential
ASTs (1.0 – 1.5 V) for comparative Pt catalyst supported on N-doped MWCNT.
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Figure S31. Structures and morphologies of Pt/Mn-PANI-PPy-PGC after various ASTs.
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Figure S32. Activity loss summary for fuel cell high potential ASTs at 0.8V and 0.6 V.
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Figure S33. Support stability AST results for different Pt/C catalysts, including E type (high
surface area carbon support), V type (Vulcan carbon support), and EA type (Highly graphitized
carbon support) supported Pt catalysts from TKK, from 1.0 to 1.5V in MEAs, which is reported
by Borup et al. in LANL.[8]
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0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.60.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
cathode: 0.099 mg/cm2, 1.5 bar air, 100% RH, Cell: 5 cm2, NR 211, 80oC.
Volta
ge /
V
j / A cm-2
BOL Post 30k cycles
Pt/PGC-20 wt%
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.60.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
cathode: 0.109 mg/cm2, 1.5 bar air, 100% RH, Cell: 5 cm2, NR 211, 80oC.
Volta
ge /
V
j / A cm-2
BOL Post 30k cycles
TEC10EA20E
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.60.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
cathode: 0.0985 mg/cm2, 1.5 bar air, 100% RH, Cell: 5 cm2, NR 211, 80oC.
Vol
tage
/ V
j / A cm-2
BOL Post 30k cycles
TEC10V20E
Figure S34. Pt/C catalyst durability ASTs (0.6-0.95 V, for 30, 000 cycles) in MEAs for Pt/PGC developed in this work and other commercially available Pt/C catalysts.
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Table S5. A detailed comparison of properties and performance enhancement between the developed PGC and the state of the art XC-72 carbon and other studied carbon supports
RDE measurements (20ug/cm2) MEA measurements (0.12mg/cm2)
1. Kresse, G. and J. Hafner, Ab initio molecular-dynamics simulation of the liquid-metal–amorphous-semiconductor transition in germanium. Physical Review B, 1994. 49(20): p. 14251.
2. Kresse, G. and J. Furthmüller, Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Physical review B, 1996. 54(16): p. 11169.
3. Blöchl, P.E., Projector augmented-wave method. Physical review B, 1994. 50(24): p. 17953.4. Kresse, G. and D. Joubert, From ultrasoft pseudopotentials to the projector augmented-wave
method. Physical Review B, 1999. 59(3): p. 1758.5. Perdew, J.P., K. Burke, and M. Ernzerhof, Generalized gradient approximation made simple.
Physical review letters, 1996. 77(18): p. 3865.6. Mittermeier, T., et al., Monometallic palladium for oxygen reduction in PEM fuel cells: particle-
size effect, reaction mechanism, and voltage cycling stability. Journal of The Electrochemical Society, 2017. 164(12): p. F1081-F1089.
7. Mukundan, R., et al., Accelerated testing of carbon corrosion and membrane degradation in PEM fuel cells. ECS Transactions, 2013. 50(2): p. 1003-1010.
8. Borup, R.L., et al., Durability Improvements through Degradation Mechanism Studies. 2014, Los Alamos National Lab.(LANL), Los Alamos, NM (United States).
9. Leontyev, I.N., et al., Characterization of the electrocatalytic activity of carbon-supported platinum-based catalysts by thermal gravimetric analysis. Mendeleev Communications, 2015. 25(6): p. 468-469.
10. Macauley, N., et al., Carbon corrosion in PEM fuel cells and the development of accelerated stress tests. Journal of The Electrochemical Society, 2018. 165(6): p. F3148-F3160.
11. Mukundan, R., et al., Accelerated testing validation. ECS Transactions, 2011. 41(1): p. 613-619.12. Chen, M., et al., Pt alloy nanoparticles decorated on large-size nitrogen-doped graphene tubes
for highly stable oxygen-reduction catalysts. Nanoscale, 2018. 10(36): p. 17318-17326.13. Larrude, D., et al., Multiwalled carbon nanotubes decorated with cobalt oxide nanoparticles.