DOE OSTI2018
Highlights: • Rutile phase TiO{sub 2} aggregates were prepared via thermal oxidation of pure Ti-discs, which is simple and inexpensive method. • TiO{sub 2} aggregates with submicron particles based sensor exhibited ultra-high response (R{sub A}/R{sub H{sub 2O}} > 10{sup 6}) to 90% RH. • Sensors based on TiO{sub 2} modified with GO exhibited improved sensitivity, stability and reproducibility. - Abstract: The development of cost-effective, robust, and reliable humidity monitoring system is nowadays in high demand. To this context, humidity sensors based on rutile TiO{sub 2} aggregates were prepared via thermal oxidation of pure Ti-discs at 1000 °C. The sensors based on only TiO{sub 2} aggregates exhibited the ultra-high response of about six orders of magnitude (R{sub A}/R{sub %RH} ∼ 10{sup 6}) to 90% RH with a response time of 28 s and excellent stability. However, these sensors showed no response to RH below 30%, which limits their use in practical applications for such RH level monitoring. Although with a reduced response in high RH, the TiO{sub 2} modified with GO showed potential to overcome this drawback. To understand their functionality, the TiO{sub 2} aggregates and TiO{sub 2}/GO were further characterized by XRD, SEM, TEM, Raman and FT-IR spectroscopy. The presented results are of high interest in terms of wide range humidity monitoring, low-cost and simple synthesis route, and high stability.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗