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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%。
Using thiourea (TU) and niobium oxalate as raw materials, N, S doped niobium pentoxide photocatalyst with Nb2O5 / TU mass ratio of 1: 1, 1: 2 and 1: 3 was prepared by solid phase method. The different photocatalysts were characterized by XRD, SEM, XRF, XPS and UV-Vis. Photocatalytic degradation of rhodamine B under UV irradiation. The XRD results show that N, S doping does not change the crystal structure of Nb 2 O 5, Nb 2 O 5 and N, S doping Nb 2 O 5 are hexagonal phase structure. The SEM results showed that pores appeared on the surface of N, S doped Nb_2O_5 and the size of the catalyst decreased. When the mass ratio of Nb_2O_5 / TU was 1: 1, the pores on the surface of the catalyst were larger and arranged regularly, which increased during photocatalysis The reaction area with rhodamine B contributes to the improvement of photocatalytic activity. XRF and XPS characterization results show that N, S doping into the Nb 2 O 5 crystal structure, where S exists in the form of S 6+, can be seen as SO 4 2- adsorption on the surface of Nb 2 O 5, part of the S ~ (6+) replaced Nb ~ (5+) while N replaced O existed in O-NbN environment. The results of UV-Vis show that the band gap of N, S doped Nb 2 O 5 narrows and redshifts, broadening the absorption range of light, which is beneficial to the improvement of photocatalytic activity. The photocatalytic results showed that the catalytic effect of degrading rhodamine B, N, S doping Nb 2 O 5 under UV irradiation was about 30% higher than that of Nb 2 O 5, especially when the mass ratio of Nb 2 O 5 / TU was 1: 1. 3 h rhodamine B degradation was 92%.