Carbon dots, an emerging class within the carbon allotrope family, have gained significant attention largely due to their versatile and tunable physico-chemical and optical properties.

Nitrogen-doping of carbon dots enhances their photoluminescent properties but not all amines passivate the surface equally. Indeed, the chemical makeup of the passivating agent is critical in tailoring the physico-chemical and optical properties of carbon dots.

Bismuth metallic nanoparticles have evoked considerable interest in catalysis owing to their small size, high surface area-to-volume ratio, and low toxicity. However, the need for toxic reductants and organic solvents in their synthesis often limits their desirability for application development. Here, we describe a green strategy to synthesize bismuth nanodots via the redox reactions between bismuth nitrate and d-glucose, in the presence of poly(vinylpyrrolidone) in the basic aqueous phase. Both reagents play a crucial role in the formation of monodisperse bismuth nanodots acting as mild reducing and capping agents, respectively. We further demonstrate that the catalytic activity of these dots via the successful reduction of the environmental contaminant 4-nitrophenol to its useful 4-aminophenol analogue requiring only 36 μg/mL nanocatalyst for 20 mM of the substrate. Moreover, they can be recovered and recycled in multiple reactions before the onset of an appreciable loss of catalytic activity. The proposed facile synthetic route and inexpensive matrix materials lead the way to access bismuth nanodots for both the fundamental study of reactions and their industrial catalysis applications.

Chiral carbon dots, prepared from the unnatural d-enantiomer of cysteine, inhibit the growth of Escherichia coli ATCC 25922 and MG1655 at a lower concentration than l-carbon dots, prepared from the l-enantiomer.

Visible-light photosensitization of metal oxides to create heterostructures for the conversion of solar to chemical energy is a promising approach to produce solar fuels and other valuable chemicals. Carbon dots have recently been considered as suitable candidates to sensitize wide-band-gap metal oxide semiconductors due to their low cost and tunable optical properties. While photocatalytic systems using carbon dots as sensitizers have been reported, transformations involving the production of value-added chemicals as well as the electron transfer mechanisms underpinning photocatalysis within such heterostructures remain underexplored. Here, we report the sensitization of zinc oxide nanowires with carbon dots for the α-heteroarylation of 1-phenylpyrrolidine with 2chlorobenzothiazole under visible-light illumination at room temperature. The carbon dots improve the light absorption of the nanowires in the visible region of the spectrum affording the use of white light to drive catalysis. From optical spectroscopy and electrochemistry investigations of the resulting nanohybrid material, the photocatalytic properties are explained by the band alignment at the zinc oxide−carbon dot junction where a series of single-electron transfers create the necessary potential to oxidize 1-phenylpyrrolidine. The resulting cascade of electron transfers into and from the carbon dots drives the α-heteroarylation to a 97% yield after 24 h.