Electronic Interactions in Illuminated Carbon Dot/MoS2 Ensembles and Electrocatalytic Activity towards Hydrogen Evolution.

The preparation, characterization, and photophysical and electrocatalytic properties of carbon dot (CD)/MoS2 ensembles is reported. Based on electrostatic interactions, ammonium-functionalized MoS2 , which was prepared upon reaction of 1,2-dithiolane tert-butyl carbamate with MoS2 followed by acidic deprotection, was coupled with CDs bearing multiple carboxylates on their periphery, as derived upon microwave-assisted polycondensation of citric acid and ethylenediamine followed by alkaline treatment. Insights into electronic interactions between the two species within CD/MoS2 ensembles emanated from absorption and photoluminescence titration assays. Efficient fluorescence quenching of CDs by MoS2 was observed and attributed to photoinduced electron/energy transfer as the decay mechanism for the transduction of the singlet excited state of CDs. Finally, the electrocatalytic performance of the CD/MoS2 ensemble was assessed towards the hydrogen evolution reaction and found to be superior to that of individual CDs species.