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. Dotting C and attracting MoS2: Aqueous, stable carbon dot (CD)/MoS2 ensembles form through electrostatic interactions (see figure). The efficient photoluminescence quenching of CDs by MoS2, together with the improved electrocatalytic performance of CD/MoS2 towards the hydrogen evolution reaction, advance the field of energy‐conversion applications.