氮化碳纳米球可见光催化降解氧氟沙星性能研究

Study on visible light photocatalytic degradation of ofloxacin by carbon nitride nanospheres

通过硬模板法合成了SiO_(2)@g-C_(3)N_(4)核壳纳米球和Ag/AgCl/SiO_(2)@g-C_(3)N_(4)复合材料,对其结构和光学性质进行表征,研究了其在可见光下降解氧氟沙星(OFX)的性能和机制。结果表明,氮化碳包覆于SiO_(2)纳米球表面,且大部分为直径400 nm左右的球体,Ag/AgCl的加入构建了异质结从而使得光生载流子的分离效率大幅提高。相比于纯g-C_(3)N_(4),Ag/AgCl/SiO_(2)@g-C_(3)N_(4)复合材料的光催化降解氧氟沙星能力显著提升,其中,当OFX初始浓度10 mg/L,催化剂投加量为0.2 g/L,在100 mW/cm^(2)的可见光照40 min后,OFX的降解率可达72.59%。自由基淬灭实验发现,在Ag/AgCl/SiO_(2)@g-C_(3)N_(4)复合材料光催化降解污染物过程中,主要活性物质为光生空穴。

SiO_(2)@g-C_(3)N_(4)Core-shell nanospheres and Ag/AgCl/SiO_(2)@g-C_(3)N_(4)composites were synthesized by hard template method,their structure and optical properties were characterized.The performance and mechanism of visible light photocatalytic degradation of ofloxacin(OFX)were investigated.The results showed g-C_(3)N_(4)is coated on the surface of SiO_(2)nanospheres,most of them are spheres with a diameter of 400 nm.The addition of Ag/AgCl constructs a heterojunction and significantly improves the separation efficiency of photogenerated carriers.Compared with pure g-C_(3)N_(4),the photocatalytic degradation of ofloxacin by Ag/AgCl/SiO_(2)@g-C_(3)N_(4)composites was significantly improved.When the initial concentration of OFX is 10 mg/L,the catalyst dosage is 0.2 g/L,and the degradation rate of OFX can reach 72.59%after 40 min of visible light irradiation at 100 mW/cm^(2).Free radical quenching experiments showed that the main active substance in the photocatalytic degradation of pollutants by Ag/AgCl/SiO_(2)@g-C_(3)N_(4)composite was photogenerated holes.