Toward alcohol synthesis from CO hydrogenation on Cu(111)-supported MoS - predictions from DFT+KMC.

In the quest for cheap and efficient catalysts for alcohol synthesis from syngas, a material of interest is single-layer MoS owing to its low cost, abundancy, and flexible structure. Because of the inertness of its basal plane, however, it is essential to find ways that make it catalytically active. Herein, by means of density functional theory based calculations of reaction pathways and activation energy barriers and accompanying kinetic Monte Carlo simulations, we show that while S vacancy row structures activate the MoS basal plane, further enhancement of chemical activity and selectivity can be achieved by interfacing the MoS layer with a metallic support. When defect-laden MoS is grown on Cu(111), there is not only an increase in the active region (surface area of active sites) but also charge transfer from Cu to MoS, resulting in a shift of the Fermi level such that the frontier states (d orbitals of the exposed Mo atoms) appear close to it, making the MoS/Cu(111) system ready for catalytic activity. Our calculated thermodynamics of reaction pathways lead to the conclusion that the Cu(111) substrate promotes both methanol and ethanol as the products, while kinetic Monte Carlo simulations suggest a high selectivity toward the formation of ethanol.