Phosphorus-doped graphene quantum dots loaded on TiO2 for enhanced photodegradation

Reducing the direct recombination of the photogenerated electron-hole pairs in a photocatalytic system is important to improve the photocatalytic efficiency. Transferring the photogenerated carriers to other adsorbates is a usual way to reduce the direct recombination probability. By synthesizing p-type phosphorus-doped graphene quantum dots (P-GQDs) to form p-n junctions with n-type TiO2 nanocomposites, the photogenerated holes of TiO2 can be effectively transferred to P-GQDs, thus the direct carrier recombination of TiO2 is decreased, resulting in the conspicuous improvement of the Methyl Orange (MO) photodegradation efficiency to 95.5% in 14 min. This work provides a new type of p-n junction in highly efficient photodegradation system.