Rational Synthesis of Polymeric Nitrogen N8-with Ultraviolet Irradiation and Its Oxygen Reduction Reaction Mechanism Study with in Situ Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy

Zhenhua Yao, Zhiyi Wu, Maocong Hu, Safa Alzaim, Joshua Young, Jinchao Dong, Jinfa Chang, Haizheng Zhuang, El Mostafa Benchafia, Yang Yang, Jianfeng Li, Zafar Iqbal, Xianqin Wang

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Polynitrogen (PN) deposited on multiwalled carbon nanotubes was synthesized by cyclic voltammetry with ultraviolet (UV) irradiation. Compared to the sample formed without UV, a larger amount of N8-was synthesized and was found to distribute more uniformly on the MWNTs with 254 nm UV irradiation, indicating that the production of more azide (N3)0radicals as the precursors for synthesis of N8-by photoexcitation of azide (N3-) ions is a rate-limiting step for PN synthesis. An oxygen reduction reaction kinetics study indicated a four-electron reaction pathway on N8-, whereas a two-electron process occurs on N3-. Analysis by in situ shell-isolated nanoparticle-enhanced Raman spectroscopy revealed that the side-on and end-on O2adsorption occurred at N8-and N3-, respectively, confirming the electron transfer process. A full direct-methanol fuel cell study shows that methanol crossover typically reduces the current density of Pt/C by ∼40% but has very little effect on the performance of the PN-MWNT catalyst after testing for 120 h. Moreover, the power density from the PN-MWNT cathode is at least twice that from a Pt/C cathode.

Original languageEnglish (US)
Pages (from-to)13034-13040
Number of pages7
JournalACS Catalysis
Volume11
Issue number21
DOIs
StatePublished - Nov 5 2021
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)

Keywords

  • SHINERS
  • UV radiation
  • direct-methanol fuel cell
  • polynitrogen
  • rate-limiting step

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