IMPROVED HYDROGENATION CATALYSTS FOR COAL-DERIVED LIQUIDS

Benzene, naphthalene and biphenyl hydrogenation in a slurry-phase reactor were used as probe reactions to investigate the influence of bimetallic catalyst formulations and altervalent carrier doping on hydrogenation activity and sulphur-poisoning characteristics. It was found that addition of a secondary metal such as Pd, Ir or Re to primary metals such as Pt, Rh, or Ru, has a beneficial influence on these parameters. Significant enhancements in hydrogen adsorption capacity, hydrogenation activity and sulphur tolerance were observed when metals were dispersed on TiO2 doped with higher-valence cations. The enhancement factors were found to be a function of the dopant concentration in the carrier. Results related to altervalent carrier doping are explained in terms of long-range electronic interactions at the metal-support interface which alter the work function of surface metal atoms.