流化床化学气相沉积法制备CNT/Fe-Ni/TiO2及其光催化性能研究

以Fe-Ni/TiO2为催化剂,采用流化床化学气相沉积法(FBCVD)在TiO2表面原位生长碳纳米管(CNT),得到CNT/Fe-Ni/TiO2复合光催化剂.通过SEM、XRD、UV-Vis等方法表征其结构和性能,以亚甲基蓝溶液降解为模型考察其光催化性能.结果表明:Fe-Ni/TiO2催化剂在FBCVD过程中,镍主要起到了CNT生长催化活性位的作用;在生长CNT后的复合光催化剂中,比例较低的Fe3+主要作为电子俘获剂,抑制TiO2光生电子空穴的复合;Ni和CNT共同起到将电子迅速地从TiO2中导出,从而降低光生电子空穴复合几率的作用.三者的协同作用显著改善了TiO2的光催化性能.其中Fe和Ni掺杂量分别为0.25mol%和4.75mol%样品的光催化活性较高,生长CNT后得到的复合光催化剂对亚甲基蓝的降解效率较纯TiO2提高约70%.

Synthesis and Photocatalytic Properties of CNT/Fe-Ni/TiO2 by Fluidized Bed-chemical Vapor Deposition Method

Fe-Ni/TiO2 was used as catalyst to synthesize carbon nanotube(CNT)/Fe-Ni/TiO2 composite photocatalyst by fluidized bed chemical vapor deposition(FBCVD)method.Carbon nanotube grew in situ on TiO2 surface.The CNT/Fe-Ni/TiO2 composite photocatalyst were characterized by X-ray diffraction(XRD),UV-Vis absorptionspectroscope and field emission scanning electron microscope(FESEM).The photocatalytic activities of preparedsamples were investigated by the photodegradation of methylene blue(MB).The results showed that Ni was charac-terized as catalytic center for CNT growth in FBCVD process.In CNT/Fe-Ni/TiO2 composite photocatalyst,Fe(Ⅲ)cation was characterized as an electron capture center and efficiently promoted the separation of photogeneratedholes and electrons.The electron transfer from TiO2 was facilitated by Ni particles and CNTs,which could reducethe electron-hole recombination.The synergistic effects of Fe-Ni and CNT significantly enhanced the photocata-lytic activity of the catalysts.The degradation ratio of MB of CNT/Fe-Ni/TiO2 doped with 0.25mol%Fe and4.75mol%Ni was increased about 70%than that of pure TiO2.