Bio-template method combined with preceramic polymer to fabricate porous titania monolith with photocatalytic activity

Bacterial cellulose (BC) is a kind of polysaccharide composed of β-1,4-glucan chains. It is secreted by bacteria, and is a renewable nanomaterial. It has been widely used in food and industrial area, owe to its high purity, excellent water-retaining capability, good mechanical strength, and environmental friendliness. On the other hand, preceramic polymer is a kind of organic-inorganic hybrid synthetic polymer, possessing good processing ability. A variety of elements, such as Si, Al, Zr, and B etc., can be incorporated into the molecular structure of preceramic polymer and can be converted to corresponding ceramics. 

In this work, monolithic titania (TiO2) aerogel was fabricated by using BC as the bio-template and preceramic polymer as titanium resource, via freeze-drying and two-step calcination process. As-prepared TiO2 aerogel BCTi-air-2 h possessed low bulk density (0.04 g/cm3), high porosity (>99%), and moderate mechanical strength. SEM images showed that TiO2 aerogel was composed of 3D reticulate TiO2 nanofibers. The anatase crystalline structure of TiO2 with crystal size around several nanometers was revealed by XRD measurements. N2 adsorption/desorption analysis indicated that TiO2 aerogel possessed high specific area (115 m2/g) and macroporous structure, which contributed to the high photocatalytic activity. Most importantly, the monolithic state will ease the usage, recycling, and regeneration of TiO2 aerogel as photocatalyst.

 Figure 1 Fabrication route for porous titania monolith

 Figure 2 Cross-sectional SEM images of porous titania monolith

 Figure 3 Methyl orange was decomposed under UV light using porous titania monolith as photocatalyst

This work has been published in Cellulose. The first author of this article is Bo-xing Zhang (South China University of Technology). The corresponding authors are Prof. Wenfeng Qiu (South China University of Technology) and Prof. Tong Zhao (South China University of Technology).

B. Zhang, H. Yu, Y. Zhang, Z. Luo, W. Han, W. Qiu,* T. Zhao,* Bacterial cellulose derived monolithic titania aerogel consisting of 3D reticulate titania nanofibers, Cellulose 2018, 25, 7189-7196

Paper link：https://link.springer.com/article/10.1007/s10570-018-2073-z

Source from South China Advanced Institute for Soft Matter Science and Technology