Radioisotopic study of CoMo/Al2O3 sulfide catalysts for HDS

Evolution and interlayer dynamics of active sites of promoted transition metal sulfide catalysts under hydrodesulfurization conditions

“…In our previous studies, we have suggested a mechanism of thiophene conversion on the surface of the TMS catalyst [18][19][20] according to which, after thiophene adsorption on an anion vacancy, the ratio between amounts of the vacancies and the surface SH groups changes and the catalyst turns into a metastable state. C-S bond hydrogenolysis in the S-organic compound is followed by hydrocarbon formation with the participation of reversibly and dissociatively adsorbed hydrogen and is accompanied by the formation of a new SH group.…”

“…We have also developed a quantitative method to evaluate the amount and mobility of sulfide sulfur participating in the H 2 S formation in the course of thiophene HDS as well as the amount and reactivity of the active sites participating in the reaction [19,23]. It was shown that mobile sulfur of unpromoted MoS 2 catalyst was equally uniform in its reactivity as the related sites.…”

Description of coordinatively unsaturated sites regeneration over MoS2-based HDS catalysts using 35S experiments combined with computer simulations

“…Besides, 35 S radioactive tracer methods were developed to determine the sulfidation process of HDS catalysts as well as to describe the HDS reaction mechanism over various catalysts under real working conditions [32,34,35,[73][74][75][76][77][78][79][80]. On the other hand, with the recent developments of the computer simulations, new insights in the state of the HDS catalysts surface [81][82][83][84] as well as an overview of the HDS mechanism over the simulated surfaces were concurrently proposed [85,86].…”

Catalyst’s Sulfur Displacement by Thiophene, as Monitored by Exchange of 35S Radiotracer

“…This is seen from the results of kinetic studies [12] indicating that the reduction of sulfur overlayers on Mo(100) in pure H 2 is much different from that in the presence of: thiophene. The existence of the so called ''rapid'' and ''slow'' siteswell known from the radiotracer studies performed by the Moscow research group [4][5][6][7]13] -supports also the differences in the productivities of sites. Consequently the answer to the question, raised above is determined on the one hand, by the site productivity correlation between HDS sites and sites, active in irreversible H 2 S uptake.…”

“…Literature data indicate a parallelism between catalyst hydrodesulfurization (HDS) activities and the amounts of exchangeable sulfur in sulfided catalysts [1][2][3][4][5]. Sulfur exchange between non-labeled sulfur ( 32 S, denoted through S) and the labeled one ( 35 S, denoted through *S) is monitored by the decrease of gas phase radioactivity of H 2 *S (i.e.…”