Supporting Information. Free-Standing 3D Porous N-Doped Graphene Aerogel Supported. Platinum Nanocluster for Efficient Hydrogen Production from

Transcription

1 Supporting Information Free-Standing 3D Porous N-Doped Graphene Aerogel Supported Platinum Nanocluster for Efficient Hydrogen Production from Ammonia Electrolysis Yufei Zhou, Guoquan Zhang *, Mingchuan Yu, Xiaojing Wang, Jinling Lv and Fenglin Yang Key Laboratory of Industrial Ecology and Environmental Engineering Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian , P.R. China * Corresponding author: guoquanz@126.com Number of pages: 14 Number of figures: 17 Number of tables: 5 S1

2 Figure S1. a) Pt/NGA modified GC electrode, b) Pt/NGA monolith, and c) the structure schematic drawing of AEC system. Figure S2. EDX spectra of GO and NGA synthesized under the conditions of: GO/D400=1:1, GO concentration=5.0 mg/ml and ph=3.0. S2

3 Figure S3. a) TGA curves, b) XRD patterns and c) Raman spectra of NGA synthesized under the condition of GO/D400=1:1, GO=5.0 mg/ml and ph=3.0. From the TGA analysis shown in Figure S3a, three stages mass loss were observed for the NGA synthesized under the condition of GO/D400=1:1, GO concentration=5.0 mg/ml and ph = 3.0. The mass loss before 100 is due to the evaporation of free water. The sharp mass loss at 350 corresponds to the carbonization of the sample for the deoxygenation. S1 The slight mass loss between attributes to the breakage of C-C, C-N bonds and nitrogen atomic rearrangement. S2 From the XRD patterns, the characteristic peak of GO at 11 is disappeared, while a broader peak at 24.4 was observed which corresponds to the (002) plane of turbostratic carbon. S3,S4 The low intensity broadening indicates that the NGA consists of thin carbon sheets, which is consistent with the SEM image. The Raman spectra of both GO and NGA present two peaks at 1588 cm -1 and 1315 cm -1 for G band and D band, respectively. The I D /I G intensity ratio of GO and NGA are greater than 1 implying the existence of the disordered carbon. S5 S3

4 Figure S4. N 2 adsorption/desorption isotherm of GA (without adding D400) and NGA synthesized under the conditions of GO/D400=1:1, calcination temperature=800 and ph=3.0. The N 2 adsorption/desorption isotherm shown in Figure S4 demonstrated that both of GA and NGA exhibits the typical type IV Langmuir isotherms with hysteresis loops, indicating the presence of mesoporous structure. S6 In comparison to GA (without adding D400), NGA has a larger BET specific surface area, which suggests that the introduction of D400 crosslinking agent enable forming the unique 3D interpenetrated porous network structure, and thus increase the specific surface area significantly. Figure S5. Digital photographs of NGA-0 and NGA-800 samples S4

5 Figure S6. SEM images of various NGA-x (x=0, 400, 600 and 800 C) materials, amplification by a) 1,000, b) 5,000 Figure S7. Electrochemical measurements of the various NGA-x (x=0, 400, 600 and 800 C) materials in 0.1 M KCl and 5 mm K 3 [Fe(CN) 6 ] solution. S5

6 Figure S8. SEM images of the GA (without adding D400) and NGA materials synthesized at various GO/D400 ratios of 4:1, 2:1, 1:1, 1:2 and 1:4 Figure S9. Electrochemical measurements of the NGA materials synthesized at various GO/D400 ratios of 4:1, 1:2, 1:1, 1:2 and 1:4 in 0.1 M KCl and 5 mm K 3 [Fe(CN) 6 ] solution. S6

7 Figure S10. The photographs: a) the compressibility of the NGA monolith, and b) The as-prepared NGA monolith in large size. Synthesis condition is GO/D400=1:1, calcination temperature=800 and ph=3.0 Figure S11. CV curve recorded during the synthesis process of Pt/NGA by the electrodeposition method. S7

8 Figure S12. HR-TEM image of Pt/NGA-800 material Figure S13. AOR activity of the NGA-800 and Pt/NGA-800. Figure S14. XPS spectra of NGA (GO/D400=1:1) annealed at different temperatures S8

9 Figure S15. XPS spectra of NGA synthesized with different GO/D400 ratios and annealed at 800. Figure S16. The recorded anode potential, cathode potential and current of AEC using the commercial 20%Pt/C electrocatalyst as both cathode and anode. The applied voltage of AEC is 0.8 V. As control, the anode potential, cathode potential and current of AEC was recorded using the commercial 20%Pt/C electrocatalysts as both cathode and anode. The applied voltage of AEC was set at 0.8 V. It is clear from Figure S16 that the anode and cathode potentials in the commercial 20%Pt/C-based AEC are positive than that in the Pt/NGA-based AEC, suggesting that the Pt/NGA presented better AOR and HER activities, respectively. The smaller current in the Pt/C-based AEC also proves a weak activity for hydrogen production. During 3 h operation, about 3.0 ml H 2 was S9

10 produced in the commercial 20%Pt/C-based AEC, which is only 35% of H 2 volume generated in the Pt/NGA-based AEC system (8.5 ml). Figure S17. XPS spectra of the fresh and used Pt/NGA-800 materials S10

11 Table S1. Parameters of various NGA hydrogels and aerogels Hydrogel Aerogel Conditions Size Volume Size Volume Mass Density (cm) (cm 3 ) (cm) (cm 3 ) (g) (mg/cm 3 ) GO:D400 GO concentrations Initial ph No D400 Φ=1.3,H= Φ=1.2,H= :1 Φ=1.7,H= Φ=1.6,H= :1 Φ=2.0,H= Φ=1.9,H= :1 Φ=2.2,H= Φ=2.1,H= :2 Φ=2.2,H= Φ=2.1,H= :4 Φ=2.2,H= Φ=2.1,H= Φ=2.1,H= Φ=2.0,H= Φ=1.7,H= Φ=1.6,H= Φ=2.2,H= Φ=2.1,H= Φ=2.4,H= Φ=2.3,H= Φ=2.2,H= Φ=2.1,H= Φ=1.6,H= Φ=1.5,H= Φ=1.6,H= Φ=1.5,H= Φ=1.6,H= Φ=1.5,H= Φ=1.6,H= Φ=1.5,H= Rs (Ω cm 2 ) Table S2. The parameters of equivalent circuit R ct (Ω cm 2 ) n1 CPE1 (0<n<1) R p (Ω cm 2 ) n2 CPE2 (0<n<1) Pt/NGA Pt/NGA Pt/NGA Pt/NGA Pt/GA-no D Pt/NGA-4: Pt/NGA-1: Pt/NGA-1: Pt/GC Pt/C S11

12 Table S3. N1s analysis of the various NGA materials at different annealed temperatures Calcination C-N=C / % C-NH-C / % N-(C 3 ) / % -NH 2 /-NH temperature chained pyridinic chained pyrrolic chained graphitic / % / C structure N structure N structure N Table S4. N1s analysis of the various NGA materials at different GO/D400 ratios C-N=C / % C-N-C / % N-(C 3 ) / % GO/D400 chained structure pyridinic N (N1) chained structure pyrrolic N (N2) craphitic N (N3) (N1+N2)/N3 4: : : Table S5. Comparison of various AEC systems AEC AEC AEC- PEMFC AEC Conditions Cell: home-made AEC, 50 ml Anode: 3D Pt/NGA monolith electrode Cathode: 3D Pt/NGA monolith electrode Electrolyte: Ammonia (0.1 M)+ KOH(1 M) Cell: 1L Anode: Pt-Ir/Pt foil (22 mm 12 mm) Cathode: Pt-Ru Electrolyte: Ammonia (1 M)+ KOH (5 M) Anode: Pt-Ir/CFP [1] (3.7 cm 3.7 cm) Cathode: Pt-Ir/CFP (3.7 cm 3.7 cm) Zero-gap electrolysis system Applied current: 0.6 A ( V) Anode: Pt/CFP Cathode: Pt/C Elctrolyte: Ammonia (1 M)+KOH (1 M) Hydrogen production 1.90 ml mg -1 Pt ml Power consumption Reference Wh g -1 H2 this work Wh g -1 H2 [5] mg -1 Pt [2] Wh g -1 H2 [6] 2.22 ml mg -1 Pt [3] Wh g s H2 [12] [1] CFP: carbon fiber paper; [2] Based on 12 ml hydrogen through mg Pt-Ir alloy; [3] Based on 20 ml hydrogen through 9 mg Pt. S12

13 REFENCES [S1] P. Kichambare, J. Kumar, S. Rodrigues and B. Kumar, Electrochemical performance of highly mesoporous nitrogen doped carbon cathode in lithium oxygen batteries, Journal of Power Sources, 2011, 196(6): [S2] Z. Yan, H. Wang, M. Zhang, Z. Jiang, T. Jiang and J. Xie, Pt supported on Mo 2 C particles with synergistic effect and strong interaction force for methanol electro-oxidation, Electrochimica Acta, 2013, 95, [S3] Y. Wang, F. Su, C. D. Wood, J. Y. Lee, and X. S. Zhao, Preparation and characterization of carbon nanospheres as anode materials in lithium-ion secondary batteries, Industrial & Engineering Chemistry Research, 2008, 47(7), [S4] T. Palaniselvam, M. O. Valappil, R. Illathvalappil and S. Kurungot, Nanoporous graphene by quantum dots removal from graphene and its conversion to a potential oxygen reduction electrocatalyst via nitrogen doping, Energy & Environmental Science, 2014, 7, [S5] D. Puthusseri, V. Aravindan, S. Madhaci and S. Ogale, 3D micro-porous conducting carbon beehive by single step polymer carbonization for high performance supercapacitors: the magic of in situ porogen formation, Energy & Environmental Science, 2014, 7, [S6] R. Shi, J. Zhao, S. Liu, W. Sun, H. Li, P. Hao, Z. Li, J. Ren, Nitrogen-doped graphene supported copper catalysts for methanol oxidative carbonylation: enhancement of catalytic activity and stability by nitrogen species, Carbon, 2018, 130, S13