五氧化二钽纳米柱的水热合成和光催化性能

以聚乙烯醇(PEG)为结构导向剂,利用水热法合成了形貌可控的Ta2O5纳米柱.采用X射线衍射、扫描电镜、透射电镜、漫反射紫外-可见光谱和光致发光光谱对所制备样品进行了表征.考察了结晶时间和Ta2O5/Sr(OH)2摩尔比等合成参数对样品形貌的影响,并在此基础上对Ta2O5纳米粒可能的生长机理进行了推测.结果表明,在PEG和Sr(OH)2存在条件下可以合成形貌可控的Ta2O5纳米柱.研究了紫外光下Ta2O5纳米柱降解罗丹明B的光催化性能,发现Ta2O5的形貌对光催化性能有很大影响, Ta2O5纳米柱的光催化性能与其长度和直径比成线性关系.催化降解反应的表观速率常数最高可达0.156 min–1,且经多次循环使用后,样品仍然保持较高的催化性能.

Hydrothermal synthesis and photocatalytic properties of tantalum pentoxide nanorods

Tantalum pentoxide (Ta2O5) nanorods were hydrothermally synthesized using polyethylene glycol (PEG) as a guiding agent. The nanorods were characterized by X‐ray diffraction, scanning and transmission electron microscopies, and diffuse reflectance ultraviolet‐visible and photolumines‐cence spectroscopies. The effects of crystallization duration and Ta2O5/Sr(OH)2 ratio on the product morphology were investigated, and a growth mechanism was proposed. Phase‐pure Ta2O5 nano‐rods with controlled morphology were formed in the presence of PEG and Sr(OH)2, which was nec‐essary to form the nanorods. Sr(OH)2 induced the surface dissolution and re‐growth of Ta2O5. PEG induced the anisotropic growth of Ta2O5 by acting as a capping agent. The products were used to photocatalytically degrade rhodamine B under ultraviolet irradiation. The catalytic activity directly correlated with the length‐diameter ratio of the Ta2O5 nanorods. A maximum apparent reaction rate constant of 0.156 min–1 was obtained. The Ta2O5 nanorods were stable during photocatalytic reac‐tion and could be recycled several times without loss of activity.