Hydrogen on unsupported ruthenium sulfide: Thermodesorption and 1H NMR studies

Michel Lacroix

doi:10.1016/0021-9517(92)90036-h

Abstract

The interaction of transition metal sulfides with hydrogen is a complex process. Understanding this process is important due to the very large number of industrial processes dealing with these systems. The main utilization of these catalysts concerns catalytic hydrotreating which involves hydrogenation reactions and C-S, C-N, and C-O bond cleavage reactions carried out in the presence of high partial pressures of hydrogen. The complexity of the interaction of hydrogen with metal sulfides is related to its double role, as reactant and as modifier of the concentration of active sites. As a matter of fact, the interaction of hydrogen with the surface of the catalyst provokes its partial reduction, leading to coordinatively unsaturated metal ions which are directly involved in the adsorptive and catalytic properties. To tackle this fundamental problem of hydrogen adsorption on ruthenium sulfide, the authors have taken the fully sulfided state as starting point and evaluated the influence of progressive desulfurization on the amount of adsorbed hydrogen. The nature of the adsorbed species was investigated using thermodesorption and [sup 1]H NMR. 20 refs., 3 figs.

Highlights

To cite this version: Michel Lacroix, Shibin Yuan, Michèle Breysse, Claudine Doremieux-Morin, Jacques Fraissard
In order to compare this large number of litera ture data the amount of adsorbed hydrogen is often expressed using the nomenclature HduxrMeo(dSe2coUmsipnogstihtieonsaomf eamprmepoanriautmionteptrraotchei omolybdate) the values of x vary between 0.012 and 0.37. This important variation of x has probably to be ascribed to different catalysts pretreatment prior to adsorption measurements, leading to different number of vacancies. This hypothesis has been demonstrated by Jalowiecki et al [4], who have reported that the activity and the hy drogen adsorption capacity of a molybde num-based catalyst is greatly dependent on the sulfur-to-molybdenum ratio
Concern ing the chemical nature of the adsorbed species, inelastic neutron scattering studies have evidenced that dissociated hydrogen resides on sulfur anions in the form of SH groups [5, 6]

Summary

Introduction

To cite this version: Michel Lacroix, Shibin Yuan, Michèle Breysse, Claudine Doremieux-Morin, Jacques Fraissard. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Hydrogen on Unsupported Ruthenium Sulfide: Thermodesorption and 1H NMR Studies

Results

Conclusion