• 文献标题:   Chemical Modification of Graphene Oxide by Nitrogenation: An X-ray Absorption and Emission Spectroscopy Study
  • 文献类型:   Article
  • 作  者:   CHUANG CH, RAY SC, MAZUMDER D, SHARMA S, GANGULY A, PAPAKONSTANTINOU P, CHIOU JW, TSAI HM, SHIU HW, CHEN CH, LIN HJ, GUO JH, PONG WF
  • 作者关键词:  
  • 出版物名称:   SCIENTIFIC REPORTS
  • ISSN:   2045-2322
  • 通讯作者地址:   Tamkang Univ
  • 被引频次:   13
  • DOI:   10.1038/srep42235
  • 出版年:   2017

▎ 摘  要

Nitrogen-doped graphene oxides (GO:N-x) were synthesized by a partial reduction of graphene oxide (GO) using urea [CO(NH2)(2)]. Their electronic/bonding structures were investigated using X-ray absorption near-edge structure (XANES), valence-band photoemission spectroscopy (VB-PES), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS). During GO:N-x synthesis, different nitrogen-bonding species, such as pyrrolic/graphitic-nitrogen, were formed by replacing of oxygen-containing functional groups. At lower N-content (2.7 at%), pyrrolic-N, owing to surface and subsurface diffusion of C, N and NH is deduced from various X-ray spectroscopies. In contrast, at higher N-content (5.0 at%) graphitic nitrogen was formed in which each N-atom trigonally bonds to three distinct sp(2)-hybridized carbons with substitution of the N-atoms for C atoms in the graphite layer. Upon nitrogen substitution, the total density of state close to Fermi level is increased to raise the valence-band maximum, as revealed by VB-PES spectra, indicating an electron donation from nitrogen, molecular bonding C/N/O coordination or/and lattice structure reorganization in GO:N-x. The well-ordered chemical environments induced by nitrogen dopant are revealed by XANES and RIXS measurements.