One-step synthesis of in-situ N-doped ordered mesoporous titania for enhanced gas sensing performance
Yan Zhang, Qiangui Yang, Xuanyu Yang, Yonghui Deng
Index: 10.1016/j.micromeso.2018.04.008
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Abstract
In-situ N-doped ordered mesoporous titania was synthesized by a simple solvent evaporation induced aggregating assembly (EIAA) method using lab-made amphiphilic diblock copolymer polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) as a structure directing agent and titanium tetrabutoxide (TBOT) as a titanium source. The obtained N-doped mesoporous titanium dioxide materials had a pore size of ∼6.2 nm, a large accessible surface area of 119 m2 g-1 and a large pore volume of 0.160 cm3 g-1, respectively, which facilitated the diffusion and transport of gas molecules. The as-prepared samples were characterized by the FT-IR spectra, Raman spectra, X-ray photoelectron spectroscopy and UV–vis absorption spectroscopy. The results showed that the nitrogen atoms were in situ incorporated into the lattice of TiO2, thus resulting in smaller crystallite size and more defects, which facilitated promoting gas sensing performance. Its response reached 17.6 for 250 ppm acetone, which was 11.4 times higher than that of their undoped TiO2-based sensors (1.54 for 250 ppm), and the fast response and recovery time were 4s and 4s, respectively.