Supplementary Information
Nano Conductive Ceramic Wedged Graphene Composites as
Highly Efficient Metal Supports for Oxygen Reduction
Peng Wu, Haifeng Lv, Tao Peng, Daping He and Shichun Mu*
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,
Wuhan University of Technology, Wuhan 430070, China
Fax: +86 27 87879468. E-mail: msc@whut.edu.cn
Scheme S1. Formation of the Pt/RGO-ZrB2 and Pt/RGO catalysts
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Figure S1. TEM image of RGO (a), RGO/ZrB2 (c) and SEM image of RGO (b),
RGO/ZrB2 (d).
2
Figure S2. (a) ORR polarization curves of Pt/RGO-ZrB2 obtained at different rotating
rates, (b) Koutecky-Levich plots of the current density reciprocal vs.ω-1/2 at different
potentials.
The ORR activities were further investigated using the Koutecky-Levich equations[1,2]:
1 1 1
1
1
 


1/ 2
J JL JK B
JK
(1)
B  0.62nFC 0( D0) 2 / 3 1/ 6
(2)
where J denotes the measured current density, JK is the kinetic current density, JL is the
diffusion-limited current density, ω is the electrode rotation rate, F is the Faraday
constant (96485 C mol-1), C0 is the bulk concentration of O2 (1.26×10-3mol L-1), D0 is
the diffusion coefficient of O2 (1.93×10-5 cm2 s-1) and ʋ is the kinetic viscosity of the
electrolyte (1.0×10-2 cm2 s-1). The electron transfer number (n) for Pt/RGO-ZrB2 is
derived from the slope.
3
Figure S3 CV curves of the Pt/RGO/ZrB2 (a), Pt/RGO (b) and Pt/C (c) before and after
ADT.
4
Figure S4. TEM image of the Pt/RGO (a,b), Pt/RGO-ZrB2 (c,d) and Pt/C (e,f )
catalysts after ADT
5
Figure S5. Nitrogen adsorption-desorption isotherms of ZrB2 and RGO-ZrB2 (hand
milling).
Figure S6. Nyquist plots for XC-72, RGO, RGO/ZrB2, ZrB2 (a); Pt/C, Pt/RGO,
Pt/RGO-ZrB2 (b) in 0.5 M H2SO4. Inset is the equivalent circuit.
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The EIS plots of all samples contain a partially overlapped semicircle. The charge
transfer resistance in different supports can be estimated from the analysis of EIS
spectra by using the software ZsimpWin based on an equivalent electrical circuit as
shown in the inset of Figure S6.b, where Rel represents the uncompensated solution
resistance, Rct is charge transfer resistance of the supporter and Qdl is a constant phase
element [3,4].
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