Dawson-type polyoxometalates photosensitized with carbon dots for photocatalytic reduction of silver ions

•Carbon dots (CDs) constitute a new emerging class of optically active carbon nanomaterials.•The versatility of the surface of CDs has allowed the formation of electrostatic complexes with several polyoxometalates (POMs) known as very efficient photocatalysts.•Such CDs-POM hybrids are particularly efficient under visible light for the reduction of silver ions chosen as a model reaction for which the mechanism has been discussed.•The use of these CDs-POM hybrids has opened the route to consider CDs as a new family of cheap and environmentally friendly-photosensitizers for photocatalytic applications. Carbon dots (CDs) are carbon-based nanoparticles (NPs) displaying remarkable light-harvesting properties. In this work, we have investigated for the first time the possibility to use CDs to photosensitize polyoxometalates (POMs). For this purpose, we have thus engineered positively charged carbon dots allowing electrostatic interactions with anionic Dawson-type POMs. Following the formation of these new POM-CDs complexes, an efficient photoinduced electron transfer between photoexcited CDs and POMs allows the reduced POM to perform reduction reactions. The reduction of silver ions into silver nanoparticles (AgNPs) has been chosen as a model reaction. [Display omitted]