The structure of the cobalt sulfide phase in carbon-supported Co and Co-Mo sulfide catalysts as studied by EXAFS and XANES

An x-ray absorption spectroscopy study was carried out on a sulfided Co/C and a Co-Mo/C catalyst, consisting of a fully sulfided Co-Mo-S phase. By comparing the EXAFS and x-ray absorption near-edge structure spectra of the catalysts with those of pure Co9S8 and CoS2 ref. compds., the Co ions in the Co-Mo-S phase have an octahedral-like S coordination while the Co ions in the Co/C catalyst have a larger fraction of octahedral Co than Co9S8