Smob/Scat

It is of interest to compare the Smob/Scat data with Sexc/Scat obtained in studies on the S-exchange of catalyst sulfide with H2S.I 1 The degree of MoOx sulfidation was 63% if sulfided with thiophene, [ 1 that by the H2S-sulfided sample — 48%.t l The fraction of exchangeable sulfur in the... 

On alumina supported Pd and Pt, the Smob/Scat was 0.2 and 0.12 the amount of mobile sulfur was 3—3.9 x 10 S atoms/mg at 533K.I 1 According to the authors opinion, the difference between the molybdena based and the noble metal catalysts, is a consequence of the attachment of a part of sulfur to the alumina support of the noble metal catalysts. The data indicate that almost all sulfur accommodated on the noble metals was mobile, i.e., exchangeable and participated in the HDS reaction. This was different from the case with molybdena-based catalysts. This observation was confirmed recently that Smob/Pd(Pd- -Pt) ratio was 0.2, both for alumina supported Pd and Pd-Pt, irrespective of the H2S partial pressure and the amount of the total sulfur uptake. 

---