海藻基CDs-Cu-TiO_(2)复合材料的制备及其光催化性能

Preparation and Photocatalytic Properties of Alga-based CDs-Cu-TiO_(2) Composite Material

光催化降解技术能够高效去除废水中的有机污染物,具有广阔的应用前景。本研究以海藻为碳源,采用微波水热法制备海藻基碳量子点(CDs),并进一步合成CDs-Cu-TiO_(2)复合材料作为可见光催化剂用于污染物降解。结果表明,复合材料中CDs、Cu^(2+)与TiO_(2)紧密结合在一起,可见光区吸收明显增强,荧光发射效率降低。CDs与Cu^(2+)的引入产生协同效应,使复合材料的禁带宽度降低到2.35 eV,并有效抑制了电子–空穴的复合。以罗丹明B为污染物模型的光催化性能实验显示,海藻基CDs-Cu-TiO_(2)复合材料在可见光照射下降解RhB的一级反应速率常数能够达到纯TiO_(2)纳米颗粒的6.4倍,150 min降解率接近100%,是TiO_(2)纳米颗粒的2倍。

Photocatalytic degradation can efficiently reduce the organic pollutants in wastewater which has broad application prospects.Herein,an algae Enteromorpha Prolifera,was used as the raw material to prepare alga-based carbon dots(CDs)through a hydrothermal method,and CDs-Cu-TiO_(2) composite nanomaterials were further synthesized as a photocatalyst for pollutant degradation.The results show that CDs,Cu^(2+)and TiO_(2) are closely combined within the composite material.Compared to the pure TiO_(2) nanoparticles,the absorption of CDs-Cu-TiO_(2) in the visible light range is significantly enhanced and the fluorescence emission efficiency is decreased.Introduction of CDs and Cu^(2+)produces a synergistic effect,which changes the band gap of the composite material to 2.35 eV,and effectively inhibits the recombination of electrons and holes.The photocatalytic degradation experiment using Rhodamine B as a model pollutant shows that under visible light irradiation the first order rate constant of degradation catalyzed by alga-based CDs-Cu-TiO_(2) reaches 6.4 times of that degraded by pure TiO_(2) nanoparticles,and the degradation efficiency after 150 min is close to 100%,which is double of the value when TiO_(2) nanoparticles apply.