Synthesis Of Bismuth Oxychloride-based Photocatalysts And Study On Their Photocatalytic Degradation Of Ciprofloxacin

The antibiotic contamination has become a critical issue that need to be solved when the antibiotic abuse is more and more serious.One of the important solutions is to develop photocatalysts with high photocatalytic activity,which could make full use of solar energy.Bi OCl has enormous potential in the application of photocatalytic degradation due to its strong oxidation,high stability and non-toxicity.However,the band gap of Bi OCl is so wide that it only absorbs UV light,and the charge carriers of Bi OCl are easy to recombine.Therefore,the photocatalytic performance of Bi OCl is poor and cannot meet current needs.In this work,element doping and incorporation of carbon nanomaterials were applied to design visible-lightdriven Bi OCl hybrids with high photocatalytic activity.Moverover,the mechanism of enhanced photocatalytic activity was studied.The main researchs have been summarized as follows:1.The carbon quantum dots(CQDs)and reduced graphene oxide(r GO)co-modified Bi OCl(Bi OCl/CQDs/r GO)was fabricated by two-step hydrothermal method.It was found that r GO greatly enhanced the adsorption capacity of Bi OCl/CQDs/r GO-10,which was 8.0 times higher than those of Bi OCl and Bi OCl/CQDs.On the other hand,r GO and CQDs significantly improved the photocatalytic performance by enhancing the charge separation and charge injection,which were 3.8 and 8.4 times higher than those of Bi OCl,respectively.Therefore,the removal efficiency of ciprofloxacin by Bi OCl/CQDs/r GO-10 reached up to 87% in 100 min due to the superior adsorption and photocatalytic performance.In addition,Bi OCl/CQDs/r GO-10 displayed high stability after four cycles.The photocatalytic mechanism and the degradation pathway of ciprofloxacin were also proposed.2.The Co-Bi OCl/CQDs photocatalyst was fabricated by one-step hydrothermal method.When the addition of Co was 0.2 mmol and the addition of CQDs was 2 m L,the photocatalyst exhibited the highest photocatalytic activity to degrade CIP.Under visible light irradiation,the degradation efficiency of ciprofloxacin by Co Bi C2 was 79.6%,with the degradation rate constant 10.5 times higher than that of Bi OCl.The photocatalytic performance was enhanced because Co and CQDs could extend the light absorption,promote the charge carrier separation and suppress the charge carrier recombination of Co Bi C2.Moreover,the photocatalytic mechanism of CIP under visible light was also studied.