Electronic interactions in illuminated carbon dots/MoS2 ensembles and electrocatalytic activity towards hydrogen evolution

Abstract

We report on the preparation, characterization and photophysical and electrocatalytic properties of carbon dots (CDs)/MoS2 ensembles. Based on electrostatic interactions, ammonium functionalized MoS2, prepared upon reaction of 1,2-dithiolane tertbutyl 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 CDs/MoS2 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 CDs/MoS2 was assessed towards the hydrogen evolution reaction and found superior as compared to that owed to the individual CDs species.