Sulfhydryl groups on the surface of molybdenum desulfurization catalysts

Abstract

The adsorption of silver ions from a pyridine solution of silver nitrate onto a cobalt-molybdenum desulfurization catalyst, molybdenum disulfide and alumina was studied. Alumina, the cobalt-molybdenum catalysts, both oxidic and reduced with hydrogen, did not react with silver nitrate. The sulfided cobalt-molybdenum catalyst and sulfided or reduced molybdenum disulfide adsorbed silver ions and the equivalent amount of protons was liberated. This process is ascribed to the presence of sulfhydryl (SH) groups on their surfaces. On this assumption, it was found that the sulfided cobalt-molybdenum catalyst contained 0.320 mmol of SH groups in 1 g, which represents about 9% of monolayer coverage. For the reduced molybdenum disulfide, the value of 0.086 mmol of SH groups in 1 g was found, which is about 24% of a monolayer. The content of sulfhydryl groups in the reduced molybdenum disulfide was not increased after sulfiding.