2D black phosphorus and tungsten trioxide heterojunction for enhancing photocatalytic performance in visible light

A novel, efficient and stable 2D black phosphorus and tungsten trioxide heterojunction (WO 3 -BPNs) was successfully synthesized using a combined hydrothermal, liquid phase exfoliating and co-precipitation method. The as-obtained WO 3 -BPNs composite was characterized by using XRD, SEM, XPS, UV-vis, etc. The results showed that the bandgap energy of the WO 3 -BPNs50 sample was 2.2 eV, which was lower than that of pure WO 3 . BPNs in the WO 3 -BPNs heterojunction as a co-catalyst effectively enhanced photo-generated electron-hole pairs separation. The synthesized WO 3 -BPNs sample significantly improved the photocatalytic performance in degrading rhodamine B (RhB) and metoprolol (MET) compared to pure WO 3 and BPNs under visible-light. The maximum RhB and MET removal efficiencies were 92% and 87%, respectively, in the WO 3 -BPNs50 (added 50 mL BPNs dispersion) sample within 120 minutes. The relevant photocatalysis mechanisms were discussed. In addition, the intermediate products in the MET photodegradation process were investigated by LC-MS technology, and the degradation pathway of MET was proposed. BPNs in the WO 3 -BPNs heterojunction acted as a co-catalyst to enhance photo-generated electron-hole pairs separation and improve degradation performance.