Supporting Information

Graphene-Supported Cobalt(III) Complex of a Tetraamidomacrocyclic

Ligand for Oxygen Reduction Reaction

Hunter A. Wayland1, Susan N. Boury1, Yahya Albkuri1, Fumiya Watanabe2, Alexandru S. Biris2,

Charlette M. Parnell2*, Anindya Ghosh1*

1Department of Chemistry, University of Arkansas at Little Rock, 2801 South University Avenue,

Little Rock, AR 72204, USA

2Center for Integrative Nanotechnology Sciences, University of Arkansas at Little Rock, 2801

South University Avenue, Little Rock, AR 72204, USA

*corresponding authors

E-mail: axghosh@ualr.edu, Phone: 501.569.8827, Fax: 501.569.8838

Figure S1. Scheme of reaction steps involved in synthesis of amidomacrocyclic ligand (1) [S1-

S3].

2

Figure S2. Synthesis of Co(III) complex (counter-ion not pictured) (2) from amidomacrocyclic

ligand (1).

(1) (2)

Cobalt(III) catalystAmidomacrocyclic ligand

1. n-butyllithium2. Cobalt(II) chloride3. Exposure to O2

3

40014002400340086

90

94

98

Wavenumber (cm-1)

% T

rans

mitt

ance

Figure S3. FT-IR spectrum of Co catalyst 2.

4

Figure S4. ESI-MS of 2 with inset depicting theoretical isotope distribution.

5

300 340 380 420 460 500 540 5800

0.1

0.2

0.3

0.4

0.5

0.6

Wavelength

Abs

orba

nce

Figure S5. UV-Vis spectrum of 2. max = 532 nm, absorbance = 0.2077 (concentration of 1.125

x 10-4 M), and ɛ = 1.846 x 103 L mol-1 cm-1.

6

Figure S6. SEM images of graphene-supported Co(III) complex nanomaterial. The crinkle-like

morphology of the graphene is well-defined and does not appear to be stacked in formation.

7

Figure S7. TEM images of 2 supported on graphene nanomaterial demonstrating features

including (a) end-on view of thickness of crinkled graphene sheets, and (b) evidence of thin

coating over graphene which may be attributed to a layer of catalyst.

ba

8

Figure S8. XRD analysis of 2 on graphene with the larger peak at 25 degrees corresponding to

rGO and the smaller peak at 43 degrees relating to GO.

9

2812832852872892912930.00E+00

3.00E+04

6.00E+04

9.00E+04

1.20E+05

1.50E+05

Binding Energy (eV)

Cou

nts/

s

Figure S9. XPS C1s narrow scan of graphene-supported Co(III) complex.

10

-0.5 -0.3 -0.1 0.1 0.3 0.5-0.8-0.7-0.6-0.5-0.4-0.3-0.2-0.1

00.10.2

Potential (V) vs Ag/AgCl

j (m

A/c

m2)

Figure S10. CV of 20 wt% Pt/C electrode in oxygen-saturated pH 2 phosphate buffer.

11

Figure S11. (a) RDE plot of Co(III) graphene nanocomposite performance at pH 2 and (b)

Koutecky-Levich plot.

12

-2.1

-1.7

-1.3

-0.9

-0.5

-0.1

Disk current

Ring current

Potential (V) vs Ag/AgCl

j (m

A/c

m2)

Figure S12. RRDE of Co(III) graphene composite at pH 9 (calculated n = 4.18).

13

Element Binding Energy Peak (eV) Atomic %

C1s 284.00 89.71

C1s Scan A 285.35 2.31

C1s Scan B 290.67 3.17

Co2p3 779.82 0.10

N1s 398.12 0.57

O1s 530.13 0.33

Co2p3 Scan A 781.72 0.12

Co2p3 Scan B 785.27 0.06

Co2p3 Scan C 788.92 0.03

N1s Scan A 398.08 0.63

N1s Scan B 399.63 0.46

N1s Scan C 404.16 0.14

O1s Scan A 531.32 1.11

O1s Scan B 532.94 0.73

O1s Scan C 536.59 0.17

Table S1. XPS analysis of Co(III) graphene nanocomposite elemental identification and

quantification.

14

References

S1. Ghosh A, Sullivan SZ, Collom SL, Pulla S (2014) Method of synthesis of tetradentate

amide macrocycle ligand and its iron(III) complex and use as oxidation or bleaching

catalyst with hydrogen peroxide. US Pat US 8722881 B2

S2. Sullivan SZ, Ghosh A, Biris AS, Pulla S, Brezden AM, Collom SL, Woods RM, Munshi

P, Schnackenberg L, Pierce BS, Kannarpady GK (2010) Fe-complex of a tetraamido

macrocyclic ligand: Spectroscopic characterization and catalytic oxidation studies. Chem

Phys Lett 498:359-365

S3. Ellis, W. C.; Tran, C. T.; Denardo, M. A.; Fischer, A.; Ryabov, A. D. & Collins, T. J.

Design of more powerful iron-TAML peroxidase enzyme mimics. J. Am. Chem. Soc.

131, 18052-18053 (2009).

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