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针对块状g-C_3N_4(BCN)的缺点,制备出拥有更高性能的二维超薄g-C_3N_4(UCN),并通过透视电子显微镜(TEM)、X射线衍射(XRD)、BET氮气吸附、紫外可见漫反射光谱(UV-vis DRS)与荧光光谱(PL)对UCN的形貌、结构、光学性能以及光催化活性进行表征.结果显示UCN具有二维超薄纳米片结构,且比表面积和孔隙体积相对BCN大大增加,并因此提供大量的活性位点和缩短物质传输距离而提高光催化活性.UV-vis DRS显示UCN的吸收光谱发生了红移,可提高对太阳光利用效率.光致发光光谱显示薄层的结构可以降低UCN的光生电子-空穴对复合率,因此提高其光催化活性.降解实验结果表明0.4g/L的UCN对恩诺沙星(ENX)降解效果最好,1h降解率为81.7%,其反应速率常数是BCN的4.1倍.ENX的光催化降解过程符合一级动力学和Langmuir–Hinshelwood模型.pH为5时ENX降解效果最好.猝灭实验表明O_2~(·-)贡献率为66.4%,是降解体系中的主要活性物质.
In order to overcome the shortcomings of bulk g-C_3N_4 (BCN), two-dimensional ultrathin g-C_3N_4 (UCN) with higher performance was prepared and characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), BET nitrogen adsorption, The morphology, structure, optical properties and photocatalytic activity of UCN were characterized by UV-vis DRS and fluorescence spectroscopy (PL) .The results showed that UCN has a two-dimensional ultrathin nanosheet structure and the specific surface area and The pore volume is greatly increased relative to BCN and therefore provides a large number of active sites and shortened material transport distances for increased photocatalytic activity. UV-vis DRS shows a red shift in the absorption spectrum of UCN to increase solar utilization efficiency. Luminescence spectra showed that the thin layer structure can reduce the recombination rate of photogenerated electron-hole pairs and thus increase the photocatalytic activity.The results of degradation experiments showed that 0.4g / L UCN had the best degradation effect on enoxacin (ENX) 1h degradation rate was 81.7% and the reaction rate constant was 4.1 times that of BCN.The photocatalytic degradation of ENX was in accordance with the first-order kinetics and the Langmuir-Hinshelwood model.The best ENX degradation was obtained when the pH was 5. The quenching experiments showed that O_2 ~ (· -) contribution rate of 66.4%, is the degradation system The main active substance.