title: The sol-gel template synthesis of porous TiO2 for a high performance humidity sensor.
abstract: This research develops a simple template assisted sol-gel process for preparing porous TiO2 for a high performance humidity sensor. Tetraethyl orthosilicate (TEOS) as a template was directly introduced into TiO2 sol formed by the hydrolysis and condensation of titanium alkoxide; the following calcination led to the formation of TiO2-SiO2 composite, and the selective removal of SiO2 by dilute HF solution led to the formation of porous structure in TiO2. The resulting porous TiO2-based sensor exhibits high sensitivity and linear response in the wide relative humidity (RH) range of 11%-95%, with an impedance variation of four orders of magnitude to humidity change. Moreover, it exhibits a rapid and highly reversible response characterized by a very small hysteresis of <1% RH and a short response-recovery time (5 s for adsorption and 8 s for desorption), and a 30-day stability test also confirms its long-term stability. Compared with pure TiO2 prepared by the conventional sol-gel method, our product shows remarkably improved performance and good prospect for a high performance humidity sensor. The complex impedance spectra were used to elucidate its humidity sensing mechanism in detail.
authors: Research Center of Nanoscience and Nanotechnology, Shanghai University, Shanghai 200444, People's Republic of China. bamboo2009@shu.edu.cn
authors: Zhuyi
authors: Z
authors: Wang
authors: Liyi
authors: L
authors: Shi
authors: Fengqing
authors: F
authors: Wu
authors: Shuai
authors: S
authors: Yuan
authors: Yin
authors: Y
authors: Zhao
authors: Meihong
authors: M
authors: Zhang