Generation of MoS 2 quantum dots by laser ablation of MoS 2 particles in suspension and their photocatalytic activity for H 2 generation
Journal of Nanoparticle Research(2016)
摘要
MoS 2 quantum dots (QDs) have been obtained in colloidal suspensions by 532 nm laser ablation (7 ns fwhp/pulse, 50 mJ/pulse) of commercial MoS 2 particles in acetonitrile. High-resolution transmission electron microscopy images show a lateral size distribution from 5 to 20 nm, but a more homogeneous particle size of 20 nm can be obtained by silica gel chromatography purification in acetonitrile. MoS 2 QDs obtained by laser ablation are constituted by 3–6 MoS 2 layers (1.8–4 nm thickness) and exhibit photoluminescence whose λ PL varies from 430 to 530 nm depending on the excitation wavelength. As predicted by theory, the confinement effect and the larger periphery in MoS 2 QDs increasing the bandgap and having catalytically active edges are reflected in an enhancement of the photocatalytic activity for H 2 generation upon UV–Vis irradiation using CH 3 OH as sacrificial electron donor due to the increase in the reduction potential of conduction band electrons and the electron transfer kinetics.
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关键词
Nanostructures,Few-layer chalcogenides,MoS,2,Photocatalytic hydrogen generation,Photoluminescence,Energy conversion
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