硅钛杂化介孔球负载金纳米粒子及其催化性能调控

以能源开发(如光解水制氢)及环境保护(如有机物降解)应用为目标, 负载型贵金属催化剂在设计、制备及理论研究方面已取得了长足的发展。本工作以具有特异形貌及结构的树枝状二氧化硅纳米球载体为基础, 通过溶胶-凝胶法在其孔道引入二氧化钛纳米颗粒形成硅钛杂化结构。通过有机改性技术, 在树枝状硅钛杂化纳米球表面接枝氨基官能团。然后, 通过浸渍法和硼氢化钠还原手段, 在杂化纳米球孔道负载超细金纳米粒子。不同手段表征结果显示实验成功制备了树枝状硅钛杂化纳米球负载金纳米颗粒复合材料。在模拟太阳光下, 所得催化剂光解水产氢量及速率为69.08 μmol·g^-1和13.82 μmol·g^-1·h^-1, 约为对比样催化剂(树枝状二氧化硅纳米球负载金纳米粒子)的7倍。在无光条件下, 其降解对硝基苯酚的表观动力学常数为6.540×10^-3 s^-1, 约为对比样的17倍(0.372×10^-3 s^-1)。由此可见, 设计合成的新型催化剂展现出优越的多功能催化活性。

Gold Nanoparticles Supported on Silica & Titania Hybrid Mesoporous Spheres and Their Catalytic Performance Regulation

In order to exploit energy sources (like photocatalytic water splitting for hydrogen production) and protect environment (like organics degradation), supported noble metal catalysts have made considerable progress in terms of design, fabrication, and theory. Herein, based on the specific morphology and structure of dendritic mesoporous silica nanospheres (DMSNs), TiO₂ nanoparticles (NPs) were introduced into the channels via Sol-Gel method, developing dendritic mesoporous silica&titania nanospheres (DMSTNs). Then, amino groups (-NH₂) were grafted onto DMSTNs surfaces by organic modification technology. Finally, ultrasmall gold (Au) NPs were anchored onto the as-prepared DMSTNs-NH₂ through impregnation method and sodium borohydride (NaBH₄) reduction. DMSTNs supported Au NPs catalysts could be successfully constructed, as verified by different methods. Under simulated sunlight for splitting water, the amount of produced H₂ by the brand-new catalysts and the corresponding rate are 69.08 µmol·g^-1 and 13.82 µmol·g^-1·h^-1, respectively, roughly. seven times of that of the contrast sample (DMSNs supported Au NPs). Without light irradiation, the apparent kinetic constant of p-nitrophenol reduction by the as-prepared catalysts is 6.540×10^-3 s^-1, about 17 times higher than that of the reference (0.372×10^-3 s^-1). ln conclusion, DMSTNs supported Au NPs exhibit good multifunctional catalytic activity.