N8 - polynitrogen stabilized on boron-doped graphene as metal-free electrocatalysts for oxygen reduction reaction

Zhenhua Yao, Maocong Hu, Zafar Iqbal, Xianqin Wang

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Polynitrogen (PN) chain was predicted theoretically to be stable at ambient pressure by intercalating in multiple graphene layers. In this work, polynitrogen (N8 -) deposited on boron-doped graphene (PN-BG) and graphene (PN-G) was synthesized experimentally by a facile cyclic voltammetry (CV) method. It was further used for oxygen reduction reaction (ORR), which showed superior activity via a four-electron pathway mechanism. BG was prepared by a one-pot hydrothermal method. Characterizations over BG substrate, including X-ray photoelectron spectroscopy, Raman specstroscopy, Brunauer-Emmett-Teller, scanning electron microscopy, and transmission electron microscopy, demonstrated that boron atoms were successfully doped into graphene matrix. The formation of polynitrogen (N8 -) on BG was confirmed by attenuated total reflection Fourier transform infrared spectroscopy and temperature-programmed desorption. A larger amount of N8 - was obtained on boron-doped graphene than that on graphene. Rotating disk electrode measurements indicated that PN-BG showed higher current density than PN-G catalyst because of the larger amount of N8 - on BG. Compared to commercial Pt/C catalyst, PN-B1G has much better methanol tolerance. Kinetics study was also carried out to investigate the ORR pathway. Natural bonding orbital analysis confirmed the mechanism. This work provides a facile strategy to modify graphene structure and efficiently stabilize N8 - on a graphene-based matrix.

Original languageEnglish (US)
Pages (from-to)160-167
Number of pages8
JournalACS Catalysis
Volume10
Issue number1
DOIs
StatePublished - Jan 3 2020

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)

Keywords

  • Boron
  • Doped graphene
  • Metal-free catalyst
  • Oxygen reduction reaction
  • Polynitrogen

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