Supporting Information

Self-assembly of N Doped 3D Porous Carbon Frameworks from Carbon

Quantum Dots and its application for Oxygen Reduction Reaction

Chao Chen1, Zexu Sun2, Yueping Li3, Liyuan Yi4, Haoming Hu5

1 School of Computing Science, Sichuan University of Science & Engineering,

Zigong, 643000, China. E-mail: chenchao1980vip@163.com; Fax: +86-813-5505878;

Tel: +86-813-5505878.

2 Powder Metallurgy Research Institute, Central South University, Changsha, 410083,

China.

3 Primary School of Jiantangpin, Yiyang, 413412, China.

4 The Seventh High School of TaoJiang, Yiyang, 413400, China.

5 Primary School of Niutian, Yiyang, 413412, China.

*Corresponding author. Tel./fax: +86-813-5505878.

E-mail address: chenchao1980vip@163.com

Supplemental Table and Figures

Figure S1. the UV-vis absorption spectrum of CQDs. Inset: photograph of CQDs ethanol solution taken under visible and UV light.

Table S1. BET results of NCF-700, NCF-800 and NCF-900.

Samplesspecific surface area (cm2 g-1)

pore volume(cm3 g-1)

NCF-700 76.75 0.243NCF-800 171.21 0.542NCF-900 154.38 0.416

Table S2. Elemental composition of the NCF samples obtained from XPS results.Samples C (at.%) O (at.%) N (at.%)NCF-700 90.31 3.28 6.42NCF-800 90.68 4.09 5.23NCF-900 90.99 4.40 4.62

Table S3. Atomic concentrations (at.%) of heterocyclic N components of NCF samples in the N 1s binding energy region.

SamplesPyridinic N Pyrrolic N Graphitic N Oxidated N~398.4 eV ~400 eV ~401.5 eV ~402-406 eV

NCF-700 41.32 % 33.85 % 14.54 % 10.29 %NCF-800 34.70 % 19.73 % 28.86 % 20.71 %NCF-900 27.62 % 21.42 % 29.17 % 21.79 %

Figure S2. CV curves of NCF-800 in N2-saturated (black line) and O2-saturated (red line) 0.1 M KOH electrolytes at a scan rate of 50 mV s-1.

Figure S3. CV curves of Pt/C (20 wt.%) in N2-saturated (black line) and O2-saturated (red line) 0.1 M KOH electrolytes at a scan rate of 50 mV s-1.

Figure S4. CV curves of CQDs in N2-saturated (black line) and O2-saturated (red line) 0.1 M KOH electrolytes at a scan rate of 50 mV s-1.

Table S1 Comparison of the ORR performance of NCF-800 and other metal-free catalysts reported in literatures under the same conditions.

CatalystEP (V vs.RHE)

Eonset (V vs.RHE)

E1/2 (V vs.RHE)

Limiting current density (mA cm-2)

n Ref.

NCF-800 0.78 0.87 0.74 5.46 3.90 This work

N-Doped Carbon Aerogels

0.75 0.78 0.68 3.82 3.50 [1]

N, P co-doped porous carbon

networks0.78 0.84 0.72 5.12 3.64 [2]

N, As co- doped CNT 0.60 1.1 0.63 5.42 3.58 [3]

N, P co-doped Graphene

0.77 0.86 0.76 4.71 3.50 [4]

N doped Graphene

0.74 0.88 0.70 3.01 3.80 [5]

N, S, P co-doped CNT

0.73 0.85 0.72 5.35 3.58 [6]

Figure S5. The durability test of Pt/C (20 %) performed in O2-saturated 0.1 M KOH electrolyte before and after 5000 extensive cycles.

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