Paper 2D+EM+IS+NS+PS+SP+SS-FrM9
Methanol Synthesis on Defect-Laden Single-Layer MoS₂ Supported on Cu(111): Results of a First Principles Study

Friday, October 23, 2015, 11:00 am, Room 212C

Despite being found to be the preferred structure in single layer MoS₂, the sulfur vacancy row does not facilitate alcohol synthesis from syngas [1] because its narrow size limits adsorption, diffusion, and formation of possible intermediates. On the Cu(111) surface, strong interactions between MoS₂ and Cu are expected to reduce the corrugations caused by sulfur vacancy rows, resulting in a larger exposure of vacancies to adsorbates which could enhance the catalytic activity of the row towards alcohol synthesis from syngas. Based on the results of our density functional theory (DFT) simulations utilizing the DFT-D3 correction for accounting the van der Waals interactions, we show that: (1) there is a significant charge transfer from the Cu(111) surface to MoS₂, enhancing its catalytic properties, (2) the binding energies of CO and dissociated H₂ increase by 0.3 eV in comparison to that on unsupported MoS₂, indicating stronger interactions, and (3) the barriers for forming intermediate species in alcohol synthesis process reduce significantly in comparison to that on unsupported MoS₂. On the basis of these energetics, we conclude the Cu(111) substrate promotes methanol synthesis from syn gas on single-layer MoS₂ with a vacancy row. We will also present the energetic pathways for the formations of other reaction products such as methane, formaldehyde, and water, as well as that of (the reverse) water gas-shift reaction.

[1] D. Le, T. B. Rawal, and T. S. Rahman, J. Phys. Chem. C118, 5346 (2014).