Zhu Qiangtao, Pan Dongyu, Sun Yangyi, Qi Dongming
Key Laboratory of Advanced Textile Materials and Manufacturing Technology and Engineering Research Center for Eco-Dyeing & Finishing of Textiles, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018, China.
Langmuir. 2022 Apr 5;38(13):4001-4013. doi: 10.1021/acs.langmuir.1c03484. Epub 2022 Mar 15.
Hollow structures in TiO materials can enhance the photocatalytic properties by reducing the diffusion length and improving the accessibility of active sites for the reactants. However, existing approaches for preparing hollow TiO materials have two drawbacks that restrict their engineering applicability: first, a heavy reliance on templates to form a hollow structure, which makes the preparation laborious, complicated, and costly; second, difficult-to-achieve high crystallization while maintaining the small grain size in calcinated TiO, which is crucial for enhancing photocatalytic activity. Herein, a simple, effective method is proposed that not only enables the preparation of hybrid TiO-SiO hollow spheres without the template fabrication and removal process via microemulsion technology but also achieves both high crystallization and a small grain size in calcinated TiO at once through the calcination of amorphous TiO with organosilane at a high temperature of 850 °C. The prepared TiO-SiO hollow spheres with tunable sizes demonstrate high photocatalytic activity with a maximum value of 133.74 × 10 min, which is superior to commercial photocatalyst P25 ( = 114.97 × 10 min). In addition, Au can be doped in the hybrid TiO-SiO shell to gain Au-doped hollow spheres that show a high value of up to 694.14 × 10 min, which is 6 times larger than that of P25 and much better than that reported in the literature. This study not only provides an effective approach to stabilize and tune the grain growth of the TiO photocatalyst during calcination but also enables the simple preparation of hollow TiO-based materials with controllable hollow nanostructures.
TiO材料中的中空结构可以通过缩短扩散长度和提高反应物活性位点的可及性来增强光催化性能。然而，现有的制备中空TiO材料的方法存在两个缺点，限制了它们的工程应用：第一，严重依赖模板来形成中空结构，这使得制备过程繁琐、复杂且成本高昂；第二，在煅烧TiO时难以在保持小晶粒尺寸的同时实现高结晶度，而这对于提高光催化活性至关重要。在此，提出了一种简单有效的方法，该方法不仅能够通过微乳液技术制备无需模板制造和去除过程的TiO-SiO复合中空球，而且通过在850℃的高温下用有机硅烷煅烧无定形TiO，一次实现煅烧TiO的高结晶度和小晶粒尺寸。所制备的尺寸可调的TiO-SiO中空球表现出高光催化活性，最大值为133.74×10 min，优于商业光催化剂P25（=114.97×10 min）。此外，可以在TiO-SiO复合壳中掺杂Au以获得Au掺杂的中空球，其表现出高达694.14×10 min的高 值，是P25的6倍，且比文献报道的要好得多。本研究不仅提供了一种在煅烧过程中稳定和调节TiO光催化剂晶粒生长的有效方法，而且能够简单地制备具有可控中空纳米结构的中空TiO基材料。
