Understanding the Reactivity of Layered Transition-Metal Sulfides: A Single Electronic Descriptor for Structure and Adsorption

Density functional theory is used to investigate the adsorption and structural properties of layered transition-metal sulfide (TMS) catalysts. We considered both the (10(1) over bar 0) M-edge and ((1) over bar 010) S-edge terminations for a wide range of pure and doped TMSs, determined their sulfur coverage under realistic operating conditions (i.e, steady-state structures), and calculated an extensive set of chemisorption energies for several important reactions. On the basis of these results, we show that the d-band center, epsilon(d), of the edge-most metal site at 0 ML sulfur coverage is a general electronic descriptor for both structure and adsorption energies, which are known to describe catalytic activity. A negative linear correlation between adsorbate-S binding and S-metal binding allows epsilon(d) to describe the adsorption of species on both metal and sulfur sites. Our results provide a significant simplification in the understanding of structure-activity relationships in TMSs and provides guidelines for the rational design and large-scale screening of these catalysts for various processes.