分级中空结构TiO_(2)纳米微球光催化剂的制备及其性能分析

Preparation and performance analysis of hierarchical hollow-structured TiO_(2) nanospherical photocatalysts

以双(乙酰丙酮基)二异丙基钛酸酯与双-[γ-(三乙氧基硅)丙基]-四硫化物为起始材料,通过水解-缩合反应合成实心TiO_(2)-SiO_(2)纳米微球;将这些微球经碱性水热反应和后续高温煅烧,制备分级中空结构TiO_(2)纳米微球光催化剂。通过TEM、DLS、FT-IR、EDS、XRD等表征手段对其形貌、单分散性、组分及晶体结构进行测试与分析;探讨碱性水热条件对分级中空结构形成的影响机理;研究煅烧温度对光催化剂性能的作用;通过罗丹明B的光催化降解实验来评估光催化剂的活性,并与商用P25进行对比。结果表明:所得纳米微球表面有明显的刺突、单分散性好,以钛酸盐为主要成分;钛酸盐的重结晶与二氧化硅的向内蚀刻是形成分级中空结构的关键;经500℃煅烧,所得催化剂保持分级中空结构,转变为锐钛矿相TiO_(2);其光催化性能卓越,对罗丹明B的降解速率常数k可达113.49×10^(-3)·min^(-1),是实心结构的3倍,是P25的1.45倍。分级中空结构TiO_(2)纳米微球光催化剂的制备方法简单有效,为光催化降解染料的研发提供了重要参考和理论指导。

Hybrid solid TiO_(2)-SiO_(2) nanospheres were synthesized through a hydrolysis-condensation reaction with bis(acetylacetonate)-diisopropyltitanium and bis-[γ-(triethoxysilyl)propyl]-tetrasulfide as starting materials.These nanospheres were then subjected to alkaline hydrothermal reaction and subsequent high-temperature calcination to prepare TiO_(2) nanoparticle photocatalysts with hierarchical hollow structure.The morphology,monodispersity,components,and crystalline phases of the photocatalysts were characterized and analyzed by using TEM,DLS,FT-IR,EDS,and XRD.The mechanism behind the formation of the hierarchical hollow structure under alkaline hydrothermal conditions was explored.The effect of the calcination temperature on the performance of the photocatalysts were examined.The activity of the photocatalysts was evaluated through photocatalytic degradation experiments of Rhodamine B,and compared with that of commercial P25.The results indicated that the nanospheres exhibited a distinct protruding surface and excellent monodispersity and titanate was the major component.The recrystallization of titanium salts and inward etching of the silica were identified as the key mechanisms in forming of the hierarchical hollow structure.After calcination at 500℃,the obtained photocatalyst maintained its hierarchical hollow structure and transformed into anatase-phase TiO_(2).These hierarchical hollow-structured photocatalysts demonstrated superior photocatalytic performance,with a degradation rate constant k of 113.49×10^(-3)·min^(-1),three times that of solid structures,and 1.45 times higher than that of P25.The preparation method for the hierarchical hollow-structured TiO_(2) nonspherical photocatalysts is simple and effective,providing important reference and theoretical guidance for the photocatalytic degradation of organic dyes.