Photoinduced synthesis of green photocatalyst Fe3O4/BiOBr/CQDs derived from corncob biomass for carbamazepine degradation: The role of selectively more CQDs decoration and Z-scheme structure

Seeking green, highly efficient and recyclable photocatalysts for emerging pollutants removal is urgent and desirable in water treatment area. In this work, novel and environmental-friendly photocatalyst Fe3O4/BiOBr/CQDs decorated by corncob biomass carbon quantum dots (CQDs) was fabricated successfully via photoinduced method for the first time. More CQDs as electrons reservoir were deposited on the (1 1 0) facet of BiOBr by photoinduced strategy compared to common hydrolysis method through morphology observation. Besides, enhanced visible light absorption and photogenerated charge transfer efficiency make Fe3O4/BiOBr/CQDs perform best photocatalytic activity towards carbamazepine (CBZ, 10 mg/L) removal, where 99.52% CBZ could be eliminated within 120 min light irradiation. Moreover, center dot O-2(-), h(+) and .OH dominated the photodegradation process and three detailed degradation pathways depicted the transformation behavior of CBZ, which were mainly attributed to Z-scheme structure construction caused by electronic bridging and up-conversion photoluminescence of biomass CQDs. A series of photoelectrochemical tests verified the existence of CQDs and Fe3O4 solved the high charge recombination rate and low electron utilization problems of BiOBr indeed. Combined with the rational utilization of corncob waste biomass, this research indicates green photocatalyst Fe3O4/BiOBr/CQDs synthesized by photoinduced method will have wide potential in water pollutant treatment in the future.