N-CQDs/N-TiO_(2)复合光催化剂的制备及其催化降解甲基橙性能研究

Preparation of N-CQDs/N-TiO_(2) composite photocatalyst and its photocatalytic degradation performance of methyl orange

采用水热法制备了一种新型的复合光催化剂N-CQDs/N-TiO_(2)。利用X射线衍射(XRD)、扫描电镜(SEM)、紫外-可见漫反射(UV-Vis DRS)、固体荧光(PL)与比表面积仪(BET)等手段对其物相、形貌及光吸收性能进行表征,并研究了N-CQDs掺杂质量比对N-CQDs/N-TiO_(2)复合光催化剂对甲基橙光降解性能的影响。结果表明:与纯N-TiO_(2)相比,0.5%N-CQDs/N-TiO_(2)复合光催化剂对甲基橙溶液的降解效率为95.43%,这归因于N-CQDs可促进纯N-TiO_(2)对可见光的吸收,同时也可降低光生电子-空穴对的复合几率。捕获实验结果表明在可见光降解甲基橙过程中主要的活性物质为超氧基团(·O_(2)^(-))和光生空穴(h+),且·O_(2)^(-)占主要地位。

In this paper,a novel composite photocatalyst N-CQDs/N-TiO_(2) was prepared by hydrothermal method.The phase,morphology and optical absorption properties of the prepared photocatalyst were characterized by XRD,SEM,UV-Vis DRS,PL and BET,respectively.The effect of the N-CQDs doping ratio on the photocatalytic degradation performance of Methyl Orange(MO)by the N-CQDs/N-TiO_(2) composite photocatalyst was investigated.The results showed that compared with pure N-TiO_(2),0.5%N-CQDs/N-TiO_(2) composite photocatalyst displayed the best degradation efficiency for MO solution,up to 95.43%,which could be attributed to the fact of promoting the absorption of visible light and reducing the recombination probability of photogenerated electron-hole pairs by N-CQDs.The results of trapping tests indicated that the main active species in the process of degradation of MO were superoxide radicals(·O_(2)^(-))and photogenerated holes(h+),and·O_(2)^(-) played a more important role.