In-situ preparation of iron(II) phthalocyanine modified bismuth oxybromide with enhanced visible-light photocatalytic activity and mechanism insight

High-efficiency interfacial separation of photoexcited electron-hole pairs and wide spectral response are the two major factors for photocatalytic performance improvement in a bismuth oxyhalide-based system. This research displayed a facile method to prepare an iron phthalocyanine/bismuth oxybromide (FePc/BiOBr) composite photocatalyst. The as-prepared sample was characterized by transmission electron microscope, UV–vis diffuse reflectance spectra, Raman spectra and X-ray photoelectron spectroscopy. The modification of FePc could enhance the visible-light absorption of BiOBr and accelerate the separation efficiency of photogenerated electron-hole pairs. As a result, the enhanced photocatalytic activity of FePc/BiOBr composites relative to pure BiOBr can be achieved, in which the 0.5 wt% FePc/BiOBr display the optimal activity for the removal of tetracycline and ciprofloxacin under visible light irradiation. Electron spin resonance (ESR) and radicals quenching experiments showed that the active species include superoxide radicals (O2−), holes (h+) and hydroxyl radicals (OH). A possible mechanism was proposed according to related experiment results. This study might be extended to the purposive improvement of photocatalytic performance of other photocatalysts by metal phthalocyanine modification.