Design and synthesis of black phosphorus quantum dot sensitized inverse opal TiO2 photonic crystal with outstanding photocatalytic activities

Quantum dot sensitized photocatalyst is designed and applied in purification of dye wastewater, using black phosphorus nanoparticles (BPQDs) as the quantum dot and inverse opal (IO) TiO2 photonic crystal as the main photocatalyst. Due to electron density change within the composite, electrons can transfer from BPQDs to IO TiO2 directionally. Bandgap energies and relative energy band positions of BPQDs and IO TiO2 further provide efficient electronic transmission channels at the heterojunction interface. Therefore, interfacial resistance for charge transfer is reduced, the production of active oxidative species is promoted, and the photo induced charge transfer proceeds through a typical type-II route. Finally, excellent photocatalytic properties of BPQDs-IO TiO2 are achieved with the highest apparent kinetic constant (kapp) of 0.046 min-1, which is more than 3 times for bare IO TiO2 (0.014 min-1) and nearly 2 times for commercial P25 TiO2 (0.027 min-1). Furthermore, long-term stability and non-toxicity make the quantum dot sensitized photocatalyst have great applications in purifying environmental water pollution.