薄荷碳点/TiO_(2)复合光催化剂的制备及其性能研究

Study on preparation and photocatalytic performance of mint carbon dots/TiO_(2) composite photocatalyst

以薄荷粉为生物碳源,采用一步水热法成功制备出薄荷碳点/TiO_(2)复合光催化剂。利用X射线衍射仪(XRD)、扫描电镜(SEM)、红外光谱(FT-IR)、孔隙比表面分析仪(BET)、表面光电压(SPS)对薄荷碳点/TiO_(2)复合光催化剂的结构、形貌、比表面积及光生电荷分离特性进行了表征;考察了薄荷碳点/TiO_(2)复合光催化剂对模拟污染物罗丹明B(RhB)的催化降解性能。结果表明,薄荷碳点改善了TiO_(2)的光催化性能,超氧自由基·O_(2)-是薄荷碳点/TiO_(2)复合催化剂光催化降解反应中的主要活性自由基。与纯TiO_(2)样品相比,2%薄荷碳点/TiO_(2)的复合光催化剂的光生电子-空穴分离速率最高,对RhB表现出最好的脱色性能,光催化活性提高了2.24倍。

In this study,mint powder was employed as biological carbon source to prepare mint carbon dots(mint-CDs)/TiO_(2) composite photocatalyst by a one-step hydrothermal method.The structure,morphology,specific surface area and photogenerated charges separation characteristics were carefully investigated by X-ray diffraction(XRD),scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FT-IR),Brunauer-Emmett-Teller(BET)method,and surface photovoltage spectroscopy(SPS).Rhodamine B(RhB)was employed as model pollutant to study the photocatalytic activities of mint-CDs/TiO_(2) photocatalysts.The results show that mint-CD improve the photocatalytic activity of TiO_(2),and superoxide free radical•O_(2)−is the main active free radical in the photocatalytic degradation reaction.When the mass ratio of mint-CDs/TiO_(2) is 2%,the composite photocatalyst demonstrates the maximum photogenerated charges separation efficiency and degradation activity for RhB,and the photocatalytic activity was increased by 2.24 times compared with reference TiO_(2).