摘要
以硫脲(TU)和草酸铌为原料,采用固相法制备Nb_2O_5/TU质量比为1∶1,1∶2,1∶3的N,S掺杂五氧化二铌光催化剂。以X射线衍射仪(XRD)、扫描电镜(SEM)、X射线荧光光谱(XRF)、X射线光电子能谱(XPS)和紫外-可见漫反射(UV-Vis)对不同光催化剂进行表征,研究了在紫外光照射条件下对罗丹明B的光催化降解效果。由XRD结果可知N,S掺杂没有改变Nb_2O_5的晶型结构,Nb_2O_5和N,S掺杂Nb_2O_5均以六方晶相结构存在。SEM结果表明,N,S掺杂Nb_2O_5表面出现孔隙,且催化剂粒径变小,当Nb_2O_5/TU质量比为1∶1时,催化剂表面孔隙较大且排列规则,在光催化过程中增大了与罗丹明B的反应面积,有助于光催化效果提高。XRF和XPS的表征结果证明,N,S掺杂进入Nb_2O_5晶体结构中,其中S以S^(6+)形式存在,可看作是以SO4_^(2-)形式吸附在Nb_2O_5表面,部分S^(6+)取代了Nb^(5+),而N取代O存在于O-NbN环境中。UV-Vis结果显示N,S掺杂Nb_2O_5带隙变窄而出现红移现象,拓宽了光的吸收范围,这有利于光催化效果的提高。光催化效果表明,在紫外光照射条件下降解罗丹明B,N,S掺杂Nb_2O_5的催化效果比Nb_2O_5提高约30%,尤其是当Nb_2O_5/TU质量比为1∶1时制备的光催化剂,3 h对罗丹明B降解效果为92%。
N, S-doped Nb205 photocatalysts were prepared by solid-state method using thiourea （TU） and niobium oxalate as raw materials, the mass ratio of Nb2Os/TU was 1 ： 1, 1 ： 2 and 1 ： 3. Different photocatalysts were characterized by X-ray diffraction （ XRD）, scanning electron microscope （ SEM）, X-ray Fluorescence （XRF） , X-ray photoelectron spectroscopy （XPS） and ultravioletvisible diffuse reflectance spectroscopy （UV-Vis）. The photocatalytic degeneration of rhodamine B under ultraviolet radiation was investigated. The XRD patterns showed that N and S doping did not change the crystal structure of Nh2O5 , and both Nb2O5 and N, Sdoped Nb2O5 existed as hexagonal phase structure. The SEM images showed that there were many pores in the surface of N, S-doped Nb2O5 , and the size of catalyst particle became smaller. Many ordinary pores appeared on the surface of N, S-doped Nb2O5 with the mass ratio of 1：1 （Nb2O5/TU） , which increased the reaction area with rhodamine B. Further characterizations by XRF and XPS showed that N and S was doped into the Nb2O5 structure, S was in the form of S6＋ , which could he regarded as SO42- adsorbed on the surface of Nb2O5 , and part of S6＋ replaced Nb5＋ , and O was replaced by N existing in the environment of O - Nb - N. UV-Vis determinations showed that the band gap of N, S-doped Nb2O5 was narrowed and a red shift appeared, indicating that the range of light absorption was broadened, which improved the photocatalytie performance. The results of photocatalytic degradation of rhodamine B showed that the catalytic effect of N and S doping Nb2O5 was about 30% higher than that of ：Nb2O5 under the condition of UV irradiation. The degrade ratio for rhodamine B was 92% when the mass ratio of Nb2O5/TU was 1： 1 under UV radiation for 3 h.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2016年第1期43-47,共5页
Chinese Journal of Rare Metals
基金
辽宁省自然科学基金项目(201202122)资助
关键词
五氧化二铌
N
S掺杂
光催化
niobium pentoxide
N, S doped
photocatalysis
