title: Study by synchrotron radiation of the structure of a working catalyst at high temperatures and pressures.
abstract: A relation among activity, composition, and structure was determined for a working catalyst by means of a stainless-steel reactor cell of novel design that permitted operation at temperatures and pressures similar to those in industrial reactors. Molybdenum K-edge x-ray absorption spectra were used to probe the structural environment of molybdenum in CoMoS/[unknown]-alumina catalysts while hydro-desulfurization of benzothiophene was proceeding at high temperature and pressure. For catalyst samples with different contents of cobalt, radial structure functions obtained from extended x-ray absorption fine structure data presented the same features as those obtained from the spectra of MoS(2)/[unknown]-alumina reference samples. Moreover, Mo-S and Mo-Mo coordination numbers were maximum for the sample with an atomic ratio of Co to (Co + Mo) of 0.33; this sample was also the most active catalyst tested.
authors.forename: M
authors.initials: M
authors.lastname: Boudart
authors.forename: R A
authors.initials: RA
authors.lastname: Betta
authors.forename: K
authors.initials: K
authors.lastname: Foger
authors.forename: D G
authors.initials: DG
authors.lastname: Löffler
authors.forename: M G
authors.initials: MG
authors.lastname: Samant