A Single Layer of MoS₂ Activates Gold for Room Temperature CO Oxidation on an Inert Silica Substrate

Abstract

We demonstrate the facile deposition of catalytically active stable Au nanoparticles on single-layer MoS 2 , on an inert oxide substrate (SiO 2 ). Unlike a gold surface, adsorption of CO on these gold particles proceeds even at room temperature. Subsequent exposure to oxygen leads to CO 2 formation and desorption along a reaction pathway described, in detail, by density functional theory. The barrier to CO oxidation, along this pathway, is less than 300 meV, corroborating the facile nature of the CO oxidation reactions in this system. X-ray photoelectron spectroscopy directly reveals that the carbon monoxide, adsorbed on Au nanoparticles on single-layer MoS 2 , can be repeatedly titrated off the substrate by exposure to oxygen. Comparison of computational results assuming a defect-laden and pristine MoS 2 substrate suggest that the pristine single-layer material may be superior in supporting this reaction.

Methanol carbonylation to acetaldehyde on Au particles supported by single-layer MoS2 grown on silica

“…The spatial homogeneity of the sample was verified by determining the Raman peak separation and photoluminescence position along a line across the substrate. The presence of Au particles on MoS 2 /SiO 2 was also confirmed with the x-ray absorption spectroscopy published elsewhere [7,57].…”

“…This revealed that the catalytic activity of metals, that are relatively inert in the bulk, can be enhanced through nanostructuring [5]. Recently [6,7], we have shown that gold nanoclusters deposited on single-layer molybdenum disulfide (MoS 2 ) coating can transform an otherwise inert substrate, silica, into a catalytic active surface for CO oxidation. This is similar to results obtained on reducible oxides, such as titania and ceria, decorated with gold nanoparticles [8][9][10][11][12][13][14].…”

Towards Higher Alcohol Formation using a single-layer MoS2 activated Au on Silica: Methanol Carbonylation to Acetaldehyde

“…The seminal finding by Haruta of CO oxidation by supported nanoscale gold particles 1 showed that gold, despite being arguably the most noble of metals, 2 can play an active role in heterogeneous catalysis. In recent work, [3][4][5] we have shown that single-layer MoS2 coating can transform an otherwise inert substrate, silica, into a catalytic active surface for e.g. CO oxidation by gold nanoclusters, similar to results obtained for reducible oxides, such as titania and ceria.…”

“…Accompanying density functional theory (DFT) calculations validate the feasibility of the formation of carbon-carbon bonds at the surface of MoS2-supported Au nanoparticles and illuminate the underlying elementary reactions steps. Continuing the success of previous computational work, [3][4][5] in which the alcohol synthesis from syngas (CO and H2) was shown to be feasible on Au13 nanoparticles stabilized by interactions with a single layer of MoS2, we use the same supercell setup to study the formation of a bond between adsorbed methyl and carbonyl species to acetyl (Fig. 4a) and subsequent hydrogenation to acetaldehyde (Fig.…”

Transition Metal Dichalcogenides for the Application of Pollution Reduction: A Review

“…Aside from that, researchers also adopted the density functional theory (DFT) calculation to explore the theoretical potential of each TMDC as the alternative catalyst for CO oxidation (CO + O 2 → CO 2 + O) and CO dissociation. For instances, studies showed that metal-doped MoS 2 (e.g., Au 29 , Cu, Ag, Co, Rh, Ni, Ir, and Fe [51][52][53]) can significantly enhance the O 2 dissociation (which is the essential step for CO oxidation). On the other hand, the latter five mentioned metals possess the greatest potential as they favor CO dissociation [52].…”