模板法制备CdSe纳米材料及其光电性能

摘要

CdSe nanotube and nanowire arrays have been fabricated in the porous anodic aluminum oxide template (AAO) by electrodeposition method.The morphology,structure and composition of the materials were characterized by scanning electron microscopy (SEM),transmission electron microscopy (TEM),X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) respectively.The photocatalytic activities of the materials were investigated by UV-vis absorption spectroscopy.The results show that CdSe nanotube and nanowire arrays can be fabricated by controlling the deposited charge.The CdSe nanomaterials are composed of mixed phase nature of hexagonal and cubic phase.It can be observed that the crystal transformation from the cubic phase to the hexagonal phase after the annealing process at 350 ℃.Meanwhile,the open-circuit potential differences (Voc) of the annealed CdSe nanomaterials have significantly increased,and photocurrent density at 0 V (versus SCE) has also improved,indicating that the annealed nanomaterials show better photoelectrochemical properties.Furthermore,the absorption edge and band gap of CdSe nanowires are about 710 nm and 1.85 eV respectively,CdSe nanotube arrays exhibit a better photoelectrochemical performance and a higher activity than nanowires for photodegrading rhodamine B with the degradation efficiency of 53.93％ under a Xe lamp irradiation for 7 h.In addition,the growth mechanism of CdSe nanomaterials in the pore walls of AAO template has also been discussed.%采用电化学沉积法,在阳极氧化铝(AAO)模板中成功制备出CdSe纳米管和纳米线.利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射分析(XRD)和能量色散X射线光谱仪(EDS)对材料的形貌、结构和元素组成进行了表征.借助紫外-可见吸收光谱等对材料光催化活性进行了研究.结果表明:通过控制沉积电量可成功制备CdSe纳米管和纳米线;CdSe纳米材料为立方晶型与六方晶型的混合,经350℃退火处理后,CdSe纳米材料中由立方晶型向六方晶型转变,光照开路电位差值明显增强,在0 V(vs SCE)电位下的光照电流密度也有所提高,光电转换性能增强;CdSe纳米线的吸收边在710 nm左右,禁带宽度约为1.85 eV,CdSe纳米管相对于CdSe纳米线具有更高的光电转换性能和光催化活性,经7h光照后,罗丹明B降解效率高达53.93％.另外,本文还讨论了CdSe纳米材料在AAO模板孔壁的生长机理.