Designing MoS2 nanocatalysts with increased exposure of active edge sites for anthracene hydrogenation reaction

Abstract

Designing MoS₂ nanocatalysts rich with active edge sites by engineering of the nanostructures is an effective strategy to enhance their catalytic activity. A series of MoS₂ nanoflowers with self-assembled nanosheets was successfully synthesized by engineering of nanostructures. The compositions and structures of MoS₂ nanoflowers were characterized by elemental analysis, XPS, TG, XRD, Raman, SEM, and HRTEM. The growth mechanism for MoS₂ samples was proposed. MoS₂ nanoflowers with a short slab of 5–10 nm, 3–5 stacking layers and expanded basal spacing of 0.98 nm were synthesized via a one-pot solvothermal synthesis method using high boiling point and viscosity ethylene glycol as solvent, maximizing the exposure of active edge sites. In the catalytic anthracene hydrogenation reaction in a slurry-phase reactor, the hydrogenation percentage and selectivity to deep hydrogenation products of the optimized MoS₂ nanoflowers are respectively 3.2 times and 31.2 times as high as those of commercial MoS₂. The structure–activity relationship of MoS₂ catalysts suggests that the engineering of nanostructures to increase the exposure of active edge sites can dramatically improve the catalytic hydrogenation performance of MoS₂ catalysts. This study provides the theoretical instructions for designing MoS₂ catalysts with improved activity. The increased understanding and research on MoS₂ catalysts will drive the industrialization of heavy oil/residue conversion into clean fuels.