Identification of electronic descriptors for catalytic activity of transition-metal and non-metal doped MoS2

Abstract

While the d-band theory offers successful electronic descriptors for catalytic activity of transition metals, transition metal compounds still need substantial theoretical input for the identification of reactivity descriptors for fast screening of earth-abundant catalysts. We study transition metal (TM) and non-metal doped MoS₂, a promising substitute for noble metals as catalysts for multiple reactions, to clarify how doping modifies the reactivity by regulating the electronic structure of the host. We find that doping can significantly change the density of states (DOS) at band edges and the position of the Fermi level, which renders the S p-band center ε_p a good descriptor for H adsorption on both TM and non-metal doped MoS₂. Dopants to the left of the host elements in the periodic table that have fewer electrons pin the Fermi level into the valence band, and those to the right that have more electrons pin the Fermi level into the conduction band, resulting in separated linear relationships between H binding energy and S p-band center. Moreover, by a close examination of the electronic structure of late TM doped systems, we identify the position of the late TM dopant induced DOS peak near the conduction band minimum (CBM), ε_TM, as a refined descriptor which shows a linear relationship for H as well as C, N, O adsorption. Finally, we generalize our descriptor to MoSe₂ and MoTe₂ to include all three anions in transition metal dichalcogenides (TMDs) and show a universal scaling relationship between the H binding energy and anion p-band center. Together we further enhance our understanding on identifying electronic descriptors for TM compounds.