Site-dependent reactivity of MoS<sub>2</sub> nanoparticles in hydrodesulfurization of thiophene.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32868769.
- Also identified by DOI 10.1038/s41467-020-18183-4 and PMC identifier 7459117.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The catalytically active site for the removal of S from organosulfur compounds in catalytic hydrodesulfurization has been attributed to a generic site at an S-vacancy on the edge of MoS<sub>2</sub> particles. However, steric constraints in adsorption and variations in S-coordination means that not all S-vacancy sites should be considered equally active. Here, we use a combination of atom-resolved scanning probe microscopy and density functional theory to reveal how the generation of S-vacancies within MoS<sub>2</sub> nanoparticles and the subsequent adsorption of thiophene (C<sub>4</sub>H<sub>4</sub>S) depends strongly on the location on the edge of MoS<sub>2</sub>. Thiophene adsorbs directly at open corner vacancy sites, however, we find that its adsorption at S-vacancy sites away from the MoS<sub>2</sub> particle corners leads to an activated and concerted displacement of neighboring edge S. This mechanism allows the reactant to self-generate a double CUS site that reduces steric effects in more constrained sites along the edge.