Kinetic studies with a sulfur-tolerant water gas shift catalyst

Experimental measurements have demonstrated high water gas shift (WGS) activity for molybdenum sulfide-based catalyst in the presence of hydrogen sulfide. The defect structure of the catalyst, controlled by the sulfur activity in the gas phase, has a dominant effect on the reaction rate. The reaction kinetics are interpreted in terms of Langmuir-Hinshelwood surface reaction. The mechanism is shown to involve a redox cycle with Mo(V) as an important species in WGS catalysis. XPS measurements provide information on the reductive sulfidation of the catalysts from the Mo(VI)-oxide state.