Understanding the trends in the hydrodesulfurization activity of the transition metal sulfides

It is shown that the trends in the hydrodesulfurization activity of the transition metal sulfides can be understood from the variation in the binding energy of sulfur to the transition metals. A model based on the ab initio calculations of Gelatt, Moruzzi, and Williams is used to describe the binding energy trends and to single out the important parameters determining them. One important aspect of the model is, that it predicts that the trends in the catalytic activity are given to a large extend by the coupling between the sulfur chemisorption energy and the sulfur-induced distortions of the metal lattice. The simple model also appears to describe promotional effects.