This journal is The Royal Society of Chemistry 13 Supplementary Information for Chemical Interaction and Imaging of Single /Graphene Sheet Studied by Scanning Transmission X-ray Microscopy and X-ray Absorption Spectroscopy Jian Wang*, Jigang Zhou*, Yongfeng Hu, and Tom Regier Canadian Light Source Inc., University of Saskatchewan, Saskatoon, SK S7N X, Canada Contents (supplementary figures and table) Fig. S1: C K-edge STXM chemical imaging of individual /N-rmGO sheets on a holey carbon film coated TEM grid. Fig. S: N K-edge STXM chemical imaging of individual /N-rmGO sheets on a holey carbon film coated TEM grid. Fig. S3: Co L-edge STXM chemical imaging of individual /N-rmGO sheets on a holey carbon film coated TEM grid. Fig. S: Correlation analysis for STXM chemical imaging. Fig. S: Co K-edge XANES spectra of /N-rmGO and NP together with the linear combination fit of the spectra. Table S1: Linear combination fitting coefficients and fitting quality (χ ) of Co K-edge XANES spectra of /N-rmGO and NP fitted by the normalized reference spectra of CoO, Co O 3 and NP. 1
Thickness (nm) Absorbance (nm -1 ) Absorbance This journal is The Royal Society of Chemistry 13.3 C 1s. C 1s. N-rmGO.3.1 Graphene elemental X-ray absorption..1. 9 3 31 3 N-rmGO 1. (d) 1. 9 3 31 3. nm (e) 1.9 Graphene sheet cross-section thickness profile... 1. 1. Distance ( m) (f) Composite map nm.7 nm Figure S1 C K-edge STXM chemical imaging of individual /N-rmGO sheets on a holey carbon film coated TEM grid, linearly scaled reference spectrum of N-rmGO (spectrum scaled to the calculated graphene elemental X-ray absorption profile of 1 nm thick material, assuming graphene density is.1 g/cm 3, same as that of graphite); reference spectrum of holey carbon obtained at a pure region on the sample; thickness map of N-rmGO, the vertical grey scale represents the material thickness in nm, the enclosed white dotted lines indicate the regions of interest, i.e. a folded graphene sheet; (d) cross-section thickness profile along the red dotted arrow in ; (e) map of holey carbon, the vertical grey scale represents the intensity ratio to the reference spectrum; (f) colour composite map, red color: N-rmGO, green color: holey carbon; the enclosed white dotted lines indicate the regions of interest.
Absorbance (nm -1 ) This journal is The Royal Society of Chemistry 13 Pre-Edge (39-39 ev).1 od Max. Abs. (3-37 ev). od nm nm N 1s: N-rmGO Thickness 17. nm.1 (d) N 1s.1.9 /N-rmGO nm.9 39 1 Figure S N K-edge STXM chemical imaging of individual /N-rmGO sheets on a holey carbon film coated TEM grid, N 1s pre-edge averaged optical density (od) image from 39 to 39 ev; N 1s averaged od image at the maximum absorption from 3 to 7 ev; N- rmgo thickness map derived from the N 1s, i.e. maximum absorption image subtracts preedge image, then scaled by the edge-jump (difference of the pre-edge and the absorption maximum, i.e..1 od nm -1 ) of (d) /N-rmGO linear reference spectrum (nm -1 ) at the N 1s. The enclosed white dotted lines indicate the regions of interest, i.e. a folded graphene sheet; (d) was obtained from the absolute absorption spectrum of /N-rmGO, i.e. Fig. c, divided by the thickness of the sample region of interest (. nm) from which the spectrum was obtained. 3
Absorbance (nm -1 ) Absorbance This journal is The Royal Society of Chemistry 13. Co p. Co p Co + rich.. elemental X-ray absorption. 77 7 79 19.3. 77 7 79 Co + rich (d). (e) nm 1.3 (f) nm Composite map nm. nm Figure S3 Co L-edge STXM chemical imaging of individual /N-rmGO sheets on a holey carbon film coated TEM grid, linearly scaled reference spectra of Co + rich and stoichiometric (spectra scaled to the calculated elemental X-ray absorption profile of 1 nm thick material, d =.11 g/cm 3 ); reference spectrum (i.e. absorption baseline) of holey carbon at the Co L-edge; and (d) thickness maps of stoichiometric and Co + rich respectively, the vertical grey scales represent the material thickness in nm; (e) map of holey carbon, the vertical grey scale represents the intensity ratio to the reference spectrum; (f) colour composite map, red color: Co + rich, green color: holey carbon, blue color: stoichiometric. The enclosed white dotted lines in, (d) and (f) indicate the regions of interest, i.e. a folded graphene sheet.
N 1s: N-rmGO Thickness (nm) This journal is The Royal Society of Chemistry 13 1 y =.x -.7 R =. 1 1 1 1 C 1s: N-rmGO Thickness (nm) Co3O Thickness (nm) 1 1 1 1 C 1s: N-rmGO Thickness (nm). (d) 1. 1. 1 1 1 1 1 N 1s: N-rmGO Thickness (nm). (e) 1. 1.. +. y = 1.x - 1. R =. 1 1 + Co rich Co3O Thickness (nm) y =.x - 1. R =. Co rich Co3O Thickness (nm) Co3O Thickness (nm). 1 1 1. 1 1 1 1 N 1s: N-rmGO Thickness (nm) C 1s: N-rmGO Thickness (nm) Figure S Correlation analysis for images from Fig. 3a to 3d of the main text, correlation plot between N-rmGO thickness derived at the C 1s and N 1s edges, i.e. Fig. 3a versus Fig. 3b; and correlation plots between Co3O and the N-rmGO thickness derived at the C 1s and N 1s, respectively, i.e. Fig. 3c versus Fig. 3a and 3b respectively; (d) and (e) correlation plots between Co+ rich Co3O and the N-rmGO thickness derived at the C 1s and N 1s, respectively, i.e. Fig. 3d versus Fig. 3a and 3b respectively. The red dashed lines in, and plots are fitted trendlines labelled with linear relationship equations and the correlation coefficients.
Normalized (E) This journal is The Royal Society of Chemistry 13 1. Co K-edge 1... /N-rmGO /N-rmGO fit /N-rmGO Co valence fit NP NP Co valence fit 771 77 773 77 Figure S Co K-edge XANES spectra of /N-rmGO and NP together with the linear combination fit of the spectra. Red line: /N-rmGO XANES spectrum, black dashed line: /N-rmGO spectrum fitted by the normalized reference spectra of CoO, Co O 3 and NP (for reference spectra see Figure in the main text), red dashed line: /N-rmGO spectrum Co valence fitted by the normalized reference spectra of CoO and Co O 3, blue line: NP XANES spectrum, blue dashed line: NP spectrum Co valence fitted by the normalized reference spectra of CoO and Co O 3. All fitting coefficients are listed in Table S1. Table S1 Linear combination fitting coefficients and fitting quality (χ ) of Co K-edge XANES spectra of /N-rmGO and NP fitted by the normalized reference spectra of CoO, Co O 3 and NP. Normalized Reference Spectra CoO Co O 3 NP /N-rmGO fit.131(.).(.).9(.).931 /N-rmGO Co valence fit.31(.9).9(.9).197 NP Co valence fit.311(.9).9(.9).99 N.B.: values in the brackets are the fitting errors. χ