摘要
以纳米锐钛矿二氧化钛(TiO2)为原料、硼氢化钠(NaBH4)为硼源和还原剂,采用一步水热法制备了硼(B)掺杂含有氧空位的B/TiO2光催化剂。利用X射线衍射(XRD)、红外光谱(IR)、紫外-可见漫反射光谱(DRS)、X射线电子能谱(XPS)、电子顺磁共振谱(EPR)等,对样品进行结构及性能表征。以亚甲基蓝(MB)作为目标降解物,进行光催化实验,考察B掺杂与氧空位对TiO2光催化性能的影响。结果表明,在紫外光照射下,B/TiO2催化反应的一级反应速率常数是单一相TiO2的1.7倍;在可见光照射下,B/TiO2催化反应的一级反应速率常数是纯石墨相氮化碳(g-C3N4)的3.2倍。反应活性物种的捕获实验表明,在体系中起光催化氧化作用的活性物种主要是空穴。光催化活性的提高归因于:适量的B掺杂和合适的氧空位的协同作用。适量的B掺杂可使TiO2的载流子捕获位增多,有效增加了样品光催化反应的氧化位点,延长了载流子的寿命和有利于电荷的传递;合适的氧空位可拓宽其光吸收范围和提高光生载流子的传导性。
By using one-step hydrothermal method,anoxic state of boron(B)-doped B/TiO2 photocatalysts were synthesized,TiO2 taken as raw material,and sodium borohydride as the boron source and reducing agent,respectively.The structure and properties of the samples were characterized by X-ray powder diffraction(XRD),infrared spectroscopy(IR),ultraviolet-visible diffuse reflectance spectroscopy(DRS),X-ray electron spectroscopy(XPS)and electron paramagnetic resonance(EPR),respectively.Photocatalytic performance test was carried out to investigate the effect of B doping and oxygen vacancy on the photocatalytic activity of titanium dioxide by using methylene blue(MB)as the degradation target.The results showed that the first-order reaction rate constant of B/TiO2 under ultraviolet irradiation was 1.7 times that of single phase TiO2;and under visible irradiation it was 3.2 times the constant of pure graphite carbon nitride(g-C3N4).The capture experiments of reactive species showed that the main active species for photocatalytic oxidation in this system were holes.The enhancement of photocatalytic activity of TiO2 could be attributed to the proper B doping,which could increase the carriers trapping sites of TiO2 and the oxidation sites,prolonging the lifetime of carriers and facilitating charge transfer.The appropriate oxygen vacancy concentration could broaden the light absorption range and improve the conductivity of photogenerated carriers.The synergistic effect of the two enhanced the photocatalytic activity.
作者
周建伟
魏正妍
孙妙
郝依伊
黄静
张炎
刘瑞霞
ZHOU Jianwei;WEI Zhengyan;SUN Miao;HAO Yiyi;HUANG Jing;ZHANG Yan;LIU Ruixia(Institute of Energy and Fuel,Xinxiang University,Xinxiang 453003,China;College of Chemistry and Chemical Engineering,Xinxiang University,Xinxiang 453003,China)
出处
《新乡学院学报》
2019年第3期11-16,21,共7页
Journal of Xinxiang University
基金
河南省科技厅科技攻关项目(192102310496)
新乡学院科技创新基金项目(15ZP05)
关键词
二氧化钛
硼氢化钠
水热法
掺杂
氧空位
光催化
titanium dioxide
sodium borohydride
hydrothermal method
doping
oxygen vacancy
photocatalysis
