Nitrogen-doped nanoporous carbon nanosheets derived from plant biomass: An. efficient catalyst for oxygen reduction reaction

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1 Electronic Supplementry Mteril (ESI) for Energy & Environmentl Science. This journl is The Royl Society of Chemistry 214 Electronic Supplementry Informtion: Nitrogen-doped nnoporous cron nnosheets derived from plnt iomss: An efficient ctlyst for oxygen reduction rection Ping Chen,* Li-Kun Wng, Gn Wng, Min-Rui Go, Jin Ge, Wen-Jing Yun, Yu-Hu Shen, An-Jin Xie, Shu-Hong Yu,* School of Chemistry nd Chemicl Engineering, Anhui University, Hefei, Anhui, 2361, P. R. Chin Division of Nnomterils nd Chemistry, Hefei Ntionl Lortory for Physicl Sciences t Microscle, Collortive Innovtion Center of Suzhou Nno Science nd Technology, Deprtment of Chemistry, University of Science nd Technology of Chin, Hefei, Anhui 2326, P. R. Chin Clirtion of reference electrodes nd conversion to RHE. The clirtion of Hg/HgO nd Ag/AgCl electrodes were performed in stndrd three-electrode system with polished Pt wires s the working nd counter electrodes, nd the Hg/HgO or Ag/AgCl electrode s the reference electrode. Electrolytes re pre-purged nd sturted with high purity H 2. Liner scnning voltmmetry (LSV) is then run t scn rte of.5 mv s 1, nd the potentil t which the current crossed zero is tken to e the thermodynmic potentil for the hydrogen electrode rections. For exmple, in.1 M KOH, the zero current point is t V, so E (RHE) = E (Hg/HgO) V; in.5 M H 2 SO 4, the zero current point is t V, so E (RHE) = E (Ag/AgCl) V. S1

2 Current (ma) M KOH hydrogen oxidtion V hydrogen evolution Current (ma) M H 2 SO 4 hydrogen oxidtion V hydrogen evolution Potentil (V versus Hg/HgO) Potentil (V versus Ag/AgCl) Fig. S1. () Mgnified SEM imge of NCS-8; () Elementl nlysis imge of the NCS-8 (squre region mrked with 1 in Fig. 2). Fig. S2. (-) SEM nd HRTEM imges of the NCS-75; (c-d) SEM nd HRTEM imges of the NCS- 85. S2

3 cintensity (. u.) Intensity (. u.) Rw ev 4.1 ev 41.2 ev ev NCS-75 Intensity (. u.) Rw 4.1 ev ev 41.2 ev ev NCS Binding energy (ev) Binding energy (ev) Rw 41.2 ev 4.1 ev ev ev CS-8 d Nitrogen content (t. %) Totl N content: 7.5 t % NCS Binding energy (ev) Pyridinic N Pyrolic N Grphic N Other N e Nitrogen content (t %) Totl N content : 5.8 t % NCS-85 f Nitrogen content (t. %) Totl N content: 1.8 t % CS-8 Pyridinic N Pyrolic N Grphic N Other N Pyridinic N Pyrolic N Grphic N Other N Fig. S3. (-c) The high-resolution N1s XPS spectr of the NCS-75, NCS-85 nd CS-8; (d-f) The content of different types of nitrogen in the NCS-75, NCS-85 nd CS-8. S3

4 Quntity Adsored (cm 3 /g STP) NCS-75 Adsorption Desorption Reltive Pressure (P/Po) Quntity Adsored (cm 3 /g STP) NCS-85 Adsorption Desorption Reltive Pressure (P/Po) Fig. S4. (-) Nitrogen dsorption-desorption isotherms of the NCS-75 nd NCS-85. D G NCS-75 NCS-8 NCS-85 Intensity 2D Rmn shift (cm ) Fig. S5. Rmn spectr of the NCS-75, NCS-8 nd NCS-85. Intensity (.u.) NCS-75 NCS-8 NCS (degree) Fig. S6. X-ry diffrction of the NCS-75, NCS-8 nd NCS-85. S4

5 j (macm ) 4 rpm 8 rpm 12 rpm 16 rpm 2 rpm Pt/C j (macm ) 4 rpm 8 rpm 12 rpm 16 rpm 2 rpm NCS c j (macm ) 4 rpm 8 rpm 12 rpm 16 rpm 2 rpm NCS Fig. S7. RDE voltmmogrms for the ORR t the Pt/C electrode (), NCS-75 electrode () nd NCS- 85 electrode (c) t the vrious rottion speeds in O 2 -sturted.1 M KOH solution. 1 Reltive Current (%) NCS-8 Pt/C Time (s) Fig. S8. Current-time (i-t) chronomperometric response of the NCS-8 nd Pt/C electrodes t.75 V (vs RHE) in O 2 -sturted.1 M KOH solution t rottion rte of 8 rpm. S5

6 j (macm ) Dry in the ir Drying t 1 o C Freezed drying Fig. S9. RDE voltmmogrms in O 2 -sturted.1 M KOH solution t room temperture (rottion speed 16 rpm, sweep rte 2 mv s 1 ) for the products y dry in the ir, y drying t 1 C nd y freezed drying (NCS-8). NCS-8 Product ctivted y KOH j (macm ) c Quntity Adsored (cm 3 /g STP) Adsorption Desorption Reltive Pressure (P/Po) Fig. S1. () RDE voltmmogrms in O 2 -sturted.1 M KOH solution t room temperture (rottion speed 16 rpm, sweep rte 2 mv s 1 ) for the NCS8 nd the typicl product ctivted y KOH efore NH 3 tretment; (-c) SEM imge nd nitrogen dsorption-desorption isotherm of the typicl product ctivted y KOH. S6

7 Fig. S11. () Opticl microscope imges of the Typh orientlis fiers () SEM imges of the cronceous erogel; () Photogrph of the Typh orientlis oil collected fter the nneling in NH 3 tmosphere. Tle S1. BET surfce re, totl pore volume nd micropore volume of the products of NCS-75, NCS-8 nd NCS-85. Products BET surfce re Totl pore volume Micropore volume (cm 3 /g) (m 2/ g) (cm 3 /g) NCS NCS NCS S7