Green synthesis of luminescent carbon dots and carbon-coated metal particles: Two birds with one stone

Abstract A one-pot green synthesis of luminescent carbon dots and carbon-coated metal (Au, Pt, Pd) particles is proposed by using the vitamin B 2 salt (riboflavin 5′-monophosphate sodium salt hydrate) as the carbon source and the reducing agent. The hydrothermal heating of B 2 salt and metal salt solution simultaneously can result in water soluble carbon dots in supernatant and carbon-coated metal particles in the precipitate. The size and the luminescent properties of the as-prepared carbon dots are dependent on the concentration of the B 2 salt in the synthesis. Moreover, the as-prepared carbon dots show both nitrogen and phosphorus doped characteristic, which is beneficial for their luminescent property. Besides the water soluble carbon dots recovered from the supernatant, there are also interesting carbon-coated metal particles recovered from the precipitates. Such metal-loaded carbon particles might have great potential applications in the catalysis field.