钾掺杂g-C_(3)N_(4)薄膜光阳极的制备及光电催化氧化降解水中双氯芬酸钠性能  

Preparation of Potassium Doped g-C_(3)N_(4) Thin Film Photoanode and Its Application in Photoelectrocatalytic Oxidation of Diclofenac Sodium in Water

作　　者：龚妍熹 王建兵[1] 柴歩瑜 韩元春 马云飞 贾超敏 GONG Yanxi;WANG Jianbing;CHAI Buyu;HAN Yuanchun;MA Yunfei;JIA Chaomin(College of Chemical and Environmental Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)化学与环境工程学院,北京100083

出　　处：《高等学校化学学报》2022年第6期258-267,共10页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:51978658)资助.

摘　　要：兼具高光学质量和电化学性能的薄膜光电极难以制备,限制了光电催化氧化技术在水处理中的的应用.本文采用原位煅烧法制备了负载在氧化铟锡(ITO)玻璃上的石墨相氮化碳(g-C_(3)N_(4))薄膜电极,并通过掺杂K^(+)提高其光电催化氧化性能;对电极进行了表征,研究了其光电催化氧化降解水中双氯芬酸钠(DCF)的效率及降解路径.结果表明,原位煅烧法能制备出高质量的K^(+)/g-C_(3)N_(4)薄膜光电极,K+的掺杂并未明显改变电极上g-C_(3)N_(4)的晶型、价态和多孔形貌,但可以提高ITO玻璃上g-C_(3)N_(4)的负载量,增强电极对可见光的响应;K^(+)的最佳掺杂浓度为0.002 mol/L,K^(+)/g-C_(3)N_(4)薄膜电极光电催化氧化降解DCF的速率常数是纯g-C_(3)N_(4)薄膜电极的1.86倍;当初始pH值为4,电压为1 V,光源强度为0.96 W/cm^(2),反应2 h后水中DCF降解率达到70%.K^(+)/g-C_(3)N_(4)薄膜电极光电催化氧化过程中,光催化氧化和电化学氧化之间存在协同作用,两者相互增强,并提高了反应过程中光生空穴(h^(+))和羟基自由基(·OH)浓度,在这两种活性物质作用下,水中DCF分别被h+氧化生成咔唑衍生物、与·OH发生加成反应生成多羟基芳香化合物,最后开环生成小分子物质.The difficulty in preparing thin film photoelectrodes with high optical quality and excellent electro-chemical property limited the application of photoelectrocatalytic oxidation process in water treatment.In this paper,g-C_(3)N_(4) thin film electrodes loaded on indium tin oxide(ITO)glass was prepared by in situ calcination method and used potassium doping to improve their photoelectrocatalytic activity.The electrodes were characterized,the photo⁃electrocatalytic degradation of diclofenac sodium(DCF)in water with them was studied,and the DCF degradation pathways were investigated.The results showed that the in situ calcination method could prepare high-quality K^(+)/g-C_(3)N_(4) thin film photoelectrodes,and the doping of K^(+) insignificantly changed the crystalline shape,valence state,and porous morphology of g-C_(3)N_(4)on the electrode.However,it could increase the loading of g-C_(3)N_(4) on ITO glass and enhance the photocurrent response of the electrode to visible light.The optimal doping concentration of K^(+) was 0.002 mol/L.The rate constant of DCF degradation in photoelectrocatalytic oxidation process with the K^(+)/g-C_(3)N_(4)thin film electrode was 1.86 times higher than that with the pure g-C_(3)N_(4)film electrode.The DCF removal rate from water in 2 h reaction time reached 70%with the initial pH of 4,applied potential of 1 V,and light intensity of 0.96 W/cm^(2).For the photoelectrocatalytic oxidation of DCF with the K^(+)/g-C_(3)N_(4)film electrode,there was a synergy between photocatalytic oxidation and electrochemical oxidation.They could optimize each other and enhance the concentration of the photogenerated holes(h^(+))and hydroxyl radicals(·OH)produced in the reaction process.Under the action of these two active substances,DCF in water was oxidized by h^(+) into carbazole derivatives,reacted with·OH to form polyhydroxy aromatic compounds,and finally occurred reaction of ring opening to form small molecules.

关 键 词：钾掺杂石墨相氮化碳薄膜光阳极 光电催化氧化 双氯芬酸钠 光催化氧化 电化学氧化 

分 类 号：O643[理学—物理化学]