N和F共掺杂C_(3)N_(4)的制备及其可见光催化性能  

Preparation and Visible Light Photocatalytic Properties of N and F Co-doped C_(3)N_(4)

作　　者：薛彪 傅炀杰 谭盟 张超 李宁毅 杨凌轩 郑淑贞 王齐[1] XUE Biao;FU Yang-Jie;TAN Meng;ZHANG Chao;LI Ning-Yi;YANG Ling-Xuan;ZHENG Shu-Zhen;WANG Qi(School of Environment Science and Engineering,Zhejiang Gongshang University,Hangzhou 310018,China)

机构地区：[1]浙江工商大学环境科学与工程学院,杭州310018

出　　处：《无机化学学报》2022年第10期2047-2055,共9页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金(No.21876154);浙江省属高校基本业务费专项资金(No.JRK22001);浙江师范大学“先进催化材料”教育部重点实验室和浙江省“固体表面反应化学”重点实验室开放课题(No.KLMEACM202104);浙江省教育厅一般科研项目(No.Y202147596)资助。

摘　　要：针对氮化碳(C_(3)N_(4))光生电荷易复合、光催化性能有限的不足,我们制备N和F共掺杂C_(3)N_(4)(NF⁃C_(3)N_(4)),以提升其光催化性能。利用NH_(4)F在高温下原位分解产生的HF和NH_(3),对C_(3)N_(4)刻蚀的同时实现N和F双元素共掺杂。以氯化铵(NH_(4)Cl)为对照,制备N掺杂C_(3)N_(4)(N⁃C_(3)N_(4))。利用扫描电子显微镜(SEM)、能谱仪(EDS)、X射线光电子能谱(XPS)、X射线衍射(XRD)、比表面积测试和电化学表征手段研究N、F共掺杂对C_(3)N_(4)形貌、成分、结构和物化性质等的影响规律。相比于C_(3)N_(4)和N⁃C_(3)N_(4),NF⁃C_(3)N_(4)呈多孔状,比表面积增大,光生电荷的生成、分离和转移均被促进,NF⁃C_(3)N_(4)光催化还原Cr(Ⅵ)的速率是C_(3)N_(4)的2.6倍、N⁃C_(3)N_(4)的1.7倍。进一步考察了不同前驱体(尿素、双氰胺和三聚氰胺)对制备C_(3)N_(4)的影响,发现以尿素为前驱体的C_(3)N_(4)与NH_(4)F的质量比为3∶2时,NF⁃C_(3)N_(4)呈现最佳的光催化性能。催化剂用量、光照强度、空穴捕获剂浓度的增加和pH的降低均能提高Cr(Ⅵ)还原速率。在NF⁃C_(3)N_(4)浓度为0.1 g·L^(-1)、pH=3、c_(EDTA⁃2Na)=2 mmol·L^(-1)、40 min可见光照射后,Cr(Ⅵ)去除率达到90%。5次循环实验表明,优化制备的NF⁃C_(3)N_(4)光催化还原Cr(Ⅵ)的性能保持良好,具有较高的稳定性。To overcome the shortcomings of carbon nitride(C_(3)N_(4)),such as easily recombination of photogenerated charges and limited photocatalytic activity,this study explored a method to prepare NF⁃C_(3)N_(4)via co⁃doping of N and F into C_(3)N_(4)with improved photocatalytic performance.Using HF and NH3 produced by the in⁃situ decomposition of NH4F at high temperature,dual elements doping was achieved while etching C_(3)N_(4).N⁃doped C_(3)N_(4)(N⁃C_(3)N_(4))was pre⁃pared by using ammonium chloride(NH4Cl)as a control sample.The effects of N and F co⁃doping on the morpholo⁃gy,composition,structure,and physicochemical properties of C_(3)N_(4)were studied using scanning electron microscope(SEM),energy dispersive spectrometer(EDS),X⁃ray photoelectron spectroscopy(XPS),X⁃ray diffraction(XRD),spe⁃cific surface area,and electrochemistry.Compared with C_(3)N_(4)and N⁃C_(3)N_(4),NF⁃C_(3)N_(4)had porous and increased specif⁃ic surface area,and the generation,separation,and transfer of photogenerated charges were promoted.The photocat⁃alytic reduction rate of Cr(Ⅵ)by NF⁃C_(3)N_(4)was 2.6 times that of C_(3)N_(4)and 1.7 times that of N⁃C_(3)N_(4),respectively.The influence of different precursors(urea,dicyandiamide,and melamine)on the preparation of C_(3)N_(4)was further investi⁃gated.It was found that when the mass ratio of C_(3)N_(4)with urea as a precursor to NH_(4)F was 3∶2,NF⁃C_(3)N_(4)showed the best photocatalytic performance.Furthermore,the reduction rate of Cr(Ⅵ) can be enhanced with the increase of cata⁃lyst dosage,light intensity,hole trapping agent concentration,and decrease in pH.After 40 min visible light irradiation with 0.1 g·L^(-1) NF⁃C_(3)N_(4),pH=3 and c_(EDTA⁃2Na)=2 mmol·L^(-1),the Cr(Ⅵ) removal efficiency reached 90%.Five cyclic runs indicated that the optimized NF⁃C_(3)N_(4)remained good performance and high stability for photocatalytic reduc⁃tion of Cr(Ⅵ).

关 键 词：光催化 C3N4 Cr(Ⅵ)还原 N、F共掺杂 

分 类 号：O614[理学—无机化学] O643.36[理学—化学]