Tailoring the Morphology of Mesoporous Titania Thin Films through Biotemplating with Nanocrystalline Cellulose

• Published in: Journal of the American Chemical Society Vol. 136; no. 16; pp. 5930 - 5937
• Main Authors: Ivanova, Alesja, Fattakhova-Rohlfing, Dina, Kayaalp, Bugra Eymer, Rathouský, Jiri, Bein, Thomas
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 23.04.2014
• Subjects: Cellulose - chemistry; Chlorophenols - chemistry; Electric Power Supplies; Nanoparticles - chemistry; Nitric Oxide - chemistry; Porosity; Solar Energy; Titanium - chemistry
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja411292u

The tunable porosity of titania thin films is a key factor for successful applications in photovoltaics, sensing, and photocatalysis. Here, we report on nanocrystalline cellulose (NCC) as a novel shape-persistent templating agent enabling the straightforward synthesis of mesoporous titania thin films. The obtained structures are highly porous anatase morphologies having well-defined, narrow pore size distributions. By varying the titania-to-template ratio, it is possible to tune the surface area, pore size, pore anisotropy, and dimensions of titania crystallites in the films. Moreover, a post-treatment at high humidity and subsequent slow template removal can be used to achieve pore widening; this treatment is also beneficial for the multilayer deposition of thick films. The resulting homogeneous transparent films can be directly spin- or dip- coated on glass, silicon, and transparent conducting oxide (TCO) substrates. The mesoporous titania films show very high activity in the photocatalytic NO conversion and in the degradation of 4-chlorophenol. Furthermore, the films can be successfully applied as anodes in dye-sensitized solar cells.