海藻基CDs-Cu-TiO2复合材料的制备及其光催化性能

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-TiO₂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、Cu²⁺与TiO₂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Cu²⁺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-TiO₂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TiO₂纳米颗粒的6.4倍, 150 min降解率接近100%, 是TiO₂纳米颗粒的2倍。

Preparation and Photocatalytic Properties of Alga-based CDs-Cu-TiO2 Composite Material

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-TiO₂ composite nanomaterials were further synthesized as a photocatalyst for pollutant degradation. The results show that CDs, Cu ²⁺ and TiO₂ are closely combined within the composite material. Compared to the pure TiO₂ nanoparticles, the absorption of CDs-Cu-TiO₂ in the visible light range is significantly enhanced and the fluorescence emission efficiency is decreased. Introduction of CDs and Cu²⁺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-TiO₂ reaches 6.4 times of that degraded by pure TiO₂ nanoparticles, and the degradation efficiency after 150 min is close to 100%, which is double of the value when TiO₂ nanoparticles apply.