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

Chemistry. 2018 Jul 20;24(41):10468-10474. doi: 10.1002/chem.201801425. Epub 2018 Jun 19.

Abstract

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.

Keywords: carbon dots; chalcogens; donor-acceptor systems; energy conversion; photochemistry.