Preparation and photocatalytic activity of red light-emitting carbon dots/P25 heterojunction photocatalyst with ultra-wide absorption spectrum

Abstract

Carbon dots have attracted growing research interest due to its unique properties, and are expected to be used in the field of photocatalysis to solve the visible absorption loss problem of TiO2 (P25). In this paper, red light-emitting carbon dots (RCDs) with high fluorescence quantum yield (40%) and RCDs/P25 heterojunction photocatalysts were synthesized by a simple and green hydrothermal method. Characterization results indicated that RCDs were successfully coupled with P25, and RCDs could effectively broaden the visible absorption region of bare P25 from 410 nm to 800 nm. The photocatalytic activity of the as-synthesized RCDs/P25 on the degradation of rhodamine B (RhB) under visible light irradiation was greatly improved compared with that of bare P25. The degradation rate of RhB by 2%RCDs/P25 reached 98.4% in 150 min, the degradation efficiency was 7.4 times that of bare P25. The RCDs played an important role in improving the photocatalytic activity of RCDs/P25, which not only increased visible light absorption, but also promoted efficient separation of photogenerated electron-hole pairs. Furthermore, the possible degradation mechanism of RCDs/P25 heterojunction photocatalyst was given.