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.