B掺杂g-C_(3)N_(4)的一步合成及可见光下降解RhB和TC研究

One-step synthesis of B-doped g-C_(3)N_(4) and degradation of RhB and TC under visible light

为研究非金属离子掺杂对g-C_(3)N_(4)光催化性能的影响,以三聚氰胺和硼酸为前驱体,采用一步煅烧法制备了B掺杂g-C_(3)N_(4)光催化剂。罗丹明B(RhB)的可见光降解实验表明,当三聚氰胺和硼酸的添加比例(质量比)为10∶0.05(0.05BCN)时显示出最好的光催化性能,表现为光照RhB 30 min降解率高达100%,远高于纯g-C_(3)N_(4)(38%)。同时,四环素(TC)降解9 min达到100%,降解速率为纯g-C_(3)N_(4)的2.09倍。基于结构表征和光学性能测量,高光催化性能可归因于B原子掺杂替代引起的带隙调制。B掺杂不仅减小了带隙且可能在带隙中引入杂质态能级,这些都能导致可见光吸收的增强和光生载流子复合的抑制,从而大大提高了光催化性能。本工作提供了一种原子级水平获取非金属元素修饰g-C_(3)N_(4)纳米片的方法,该材料可作为一种在可见光下具有良好稳定性的RhB降解光催化剂。

To study the effects of nonmetal ion doping on the photocatalytic performance of g-C_(3)N_(4),taking melamine and boric acid as precursors,we prepared B-doped g-C_(3)N_(4) photocatalyst by one-step calcination method.The visible light degradation experiment of rhodamine B(RhB)showed that when the ratio(mass ratio)of melamine to boric acid was 10:0.05(0.05BCN),it had the best photocatalytic performance.The RhB degradation rate was up to 100%after 30 min of illumination,which was much higher than that of pure g-C_(3)N_(4)(38%).Meanwhile,tetracycline(TC)degradation reached 100%in 9 min,and the degradation rate was 2.09 times that of pure g-C_(3)N_(4).On the basis of the structural characterization and optical performance measurement,the high photocatalytic performance could be attributed to the band gap modulation caused by the doping substitution of B atoms.Boron doping not only reduced the band gap,but also might introduce impurity energy levels in the band gap,which can lead to the enhancement of light absorption and the inhibition of photogenerated carrier recombination,so as to greatly improve the photocatalytic performance.This work provides a method to obtain nonmetallic element modified g-C_(3)N_(4) nanosheets at the atomic level as a photocatalyst for RhB degradation with good stability under visible light.