g-C_3N_4纳米片的合成及可见光催化降解亚甲基蓝

Synthesis of g-C_3N_4 Nanosheets and Applications in Photocatalytic Degradation of Methylene Blue under Visible Light Irradiation

以柠檬酸钠和尿素为前驱体,采用低温固相合成技术,制备了石墨氮化碳(g-C_3N_4)光催化剂.利用X射线衍射(XRD)、透射电子显微镜(TEM)、紫外-可见光吸收光谱(UV-vis)、光致发光光谱(PL)、光电流响应及电化学阻抗谱(EIS)等对光催化剂的结构和性能进行了表征.结果表明:制备的g-C_3N_4呈片状形貌,尺寸小于50nm,具有较高的光生电子空穴分离效率.在H2O2助催化剂辅助下,可见光照射120min,g-C_3N_4纳米片催化剂对10mg·L-1亚甲基蓝(MB)溶液的降解率达到95.4%.荧光光谱法表征结果表明降解过程中有羟基自由基生成.

The g-C3N4 nanosheets were synthesized by a low temperature solid phase method with urea and sodium citrate as the precursors. The resultant gC3N4 nanosheets were characterized through X-ray diffraction （XRID）, transmission electron microscopy （TEM）, UV vis absorption spectroscopy （UVvis） and photoluminescence （PL） spectra, photocurrent and electrochemical impedance spectra （EIS） measurement. The results show that the as prepared g-C3N4 has a sheet shape with a size less than 50 nm, and high separation efficiency of photogenerated electrons and holes. The photocatalytic activities of the as prepared gC3N4 were evaluated by the degradation of methylene blue （MB）. After 120min visible light irradiation, the degradation rate of MB with mass concentration of 10 mg · L ^-1 can be reach 95. 4%, by using gC3N4 nanosheets photocatalyst in presence of H2O2. The hydroxyl radicals （· OH） are detected in the reaction.