Dative bonding as a mechanism for enhanced catalysis on the surface of MoS2

Abstract

Transition-metal dichalcogenide (TMD) layers have been a subject of widespread interest as platforms for electronic devices. However, the low chemical activity of their basal plane results in several technological bottlenecks, including high contact resistance at TMD–electrode interfaces, difficult growth of high-quality gate-oxide layers, and challenging functionalization. The simplest, and perhaps only, approach to overcoming those limitations may be to exploit dative bonding. The effect can enhance binding on TMDs, since their chalcogen nonbonding lone-pair orbitals can function as electron donors. Therefore, it should also be able to impact the surface catalysis for reactions that produce acceptors. This computational study seeks to investigate whether S→P dative bonding may be an effective mechanism for catalysis on the surface of MoS2, and whether the sheet can be functionalized via chemical reactions enabled by the binding of PHn and PCln. The results show that the bonding facilitates the PH functionalization of MoS2. The interaction is strong (1.11 eV), making the whole process exothermic, and the activation energy notably reduced (from 2.08 to 0.5 eV). Furthermore, the mechanism is intrinsically selective, which could prove a vital feature for future advancements in TMD-based electronics, since it could steer selected processes towards surface functionalization or thin-film growth.