Graphene quantum dots as efficient, metal-free, visible-light-active photocatalysts

This paper reports on new applications of water-dispersible graphene quantum dots (GQDs) that we recently developed. The prepared GQDs not only show broad absorption in the visible spectrum from 400 to 700 nm, but can also serve as smart photosensitizers with high singlet oxygen (O-1(2)) production under visible-light irradiation (>= 420 nm). We showed that the prepared GQDs can potentially be used as a metal-free, visible-light-active, sensitized photocatalyst via energy transfer mechanism, in which the light energy was converted by GQDs to produce O-1(2), which can kill nearby microorganisms and degrade organic dyes.