Science Advances

Supplementary Materials

This PDF file includes:

  • Modeling and simulation details
  • table S1. Elemental analysis of C, N, O, and Si in original CNS, O-etched CNS, and glassy carbon by energy dispersive x-ray spectrometry elemental mapping.
  • table S2. Partial current densities (mA cm−2) for CNS, oxygen-etched CNS, glassy carbon, and CNS with argon gas.
  • table S3. Comparison of open-circuit potentials and polarizations of original CNS, O-etched CNS, and glassy carbon in 0.25 M KClO4.
  • fig. S1. Representative TEM images of the CNS electrode.
  • fig. S2. The variation of surface electric field Es calculated along the normal direction at the tip of a CNS for different tip radii in the case of desolvated Li+ counterion and of solvated Li+ counterion.
  • fig. S3. Molecular dynamics simulation of electric double layers near a carbon nanosphere immersed in LiCl solution.
  • fig. S4. Regression curves for ammonia quantification.
  • fig. S5. SEM micrographs of CNS surface.
  • fig. S6. SEM micrographs for the side view of CNS.
  • fig. S7. XPS spectra of CNS.
  • fig. S8. The overall current density (red curve) and formation rate (blue dots) with time at −1.19 V versus RHE.
  • fig. S9. CP experiment to investigate stability of the electrode during the initial 5 hours of the reaction, using a larger (4.8 cm2) electrode to observe changes with respect to electrolyte composition.
  • fig. S10. Oxygen-etched CNS showing smoother texture compared to unetched CNS.
  • fig. S11. Correlated orbital levels calculated for three outer valence orbitals and three virtual orbitals at the level of EPT/aug-cc-pVTZ as a function of electric field strength.
  • fig. S12. Ultravoilet photoelectron spectroscopy and work functions of emersed CNS.
  • fig. S13. Ultraviolet photoelectron spectroscopy of pristine, unemersed CNS.
  • fig. S14. Ultraviolet photoelectron spectroscopy of O-etched CNS and glassy carbon.
  • fig. S15. Mass spectra of double-silylated product for ammonia from electrochemical N2 reduction.
  • fig. S16. Mass spectra of 14N and 15N products in the mass region of the molecular ion.
  • References (44–54)

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