TY - JOUR
T1 - New interpretation and approach to curve fitting synchrotron X-ray photoelectron spectra of (Fe,Ni)9S8 fracture surfaces
AU - Pettifer, Zoe E.
AU - Quinton, Jamie S.
AU - Skinner, William M.
AU - Harmer, Sarah L.
PY - 2020/2/28
Y1 - 2020/2/28
N2 - The surface electronic structure of (Fe,Ni)9S8 was investigated using synchrotron X-ray photoelectron spectroscopy (SXPS). SXPS S 2p and valence band (VB) spectra, collected as a function of photon energy, have resolved two distinct bulk states and two surface chemical states present at (Fe,Ni)9S8 fracture surfaces. The SXPS S 2p spectra show two distinct sulfur sites within the lattice that have been attributed to 4-coordinate sulfur at 161.7 eV, and 5-coordinate sulfur at 162.2 eV. Upon fracture, sulfur sites are exposed at multiple fracture planes and lose at least one bonding partner, resulting in surface 3-coordinate sulfur at 161.1 eV, and a slightly broader peak at 161.7 eV attributed to 4-coordinate sulfur surface monomer species overlapping the bulk 4-coordinate species. Significant asymmetric tail shapes were observed in each of the S 2p spectra and have been identified as ligand-to-metal charge transfer satellites (LMCT). A practical approach for curve fitting the (Fe,Ni)9S8 XPS spectra has been proposed.
AB - The surface electronic structure of (Fe,Ni)9S8 was investigated using synchrotron X-ray photoelectron spectroscopy (SXPS). SXPS S 2p and valence band (VB) spectra, collected as a function of photon energy, have resolved two distinct bulk states and two surface chemical states present at (Fe,Ni)9S8 fracture surfaces. The SXPS S 2p spectra show two distinct sulfur sites within the lattice that have been attributed to 4-coordinate sulfur at 161.7 eV, and 5-coordinate sulfur at 162.2 eV. Upon fracture, sulfur sites are exposed at multiple fracture planes and lose at least one bonding partner, resulting in surface 3-coordinate sulfur at 161.1 eV, and a slightly broader peak at 161.7 eV attributed to 4-coordinate sulfur surface monomer species overlapping the bulk 4-coordinate species. Significant asymmetric tail shapes were observed in each of the S 2p spectra and have been identified as ligand-to-metal charge transfer satellites (LMCT). A practical approach for curve fitting the (Fe,Ni)9S8 XPS spectra has been proposed.
KW - Australia
KW - Sulfide mineral surface characterisation
KW - Sulfur 2p XPS curve fitting
KW - Surface species
KW - Synchrotron X-ray photoelectron spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=85075361212&partnerID=8YFLogxK
UR - http://purl.org/au-research/grants/arc/FT110100099
U2 - 10.1016/j.apsusc.2019.144458
DO - 10.1016/j.apsusc.2019.144458
M3 - Article
AN - SCOPUS:85075361212
SN - 0169-4332
VL - 504
JO - Applied Surface Science
JF - Applied Surface Science
M1 - 144458
ER -