Size-Independent and Ultrahigh CO Gas Sensor Based on TiO<inf>2</inf>Modified ZnO Tetrapods

Abstract

© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim ZnO tetrapods modified by TiO2powder are synthesized using a simple fast thermal oxidation method, and theirs CO sensing properties are investigated. The ZnO tetrapods modified by TiO2powder sensor is tested at 250–400 °C under different CO concentrations compared with pure ZnO tetrapods, ZnO nanoparticle, and ZnO powder sensors. With a good crystallinity and a high pore size, the ZnO tetrapods modified by TiO2powder sensor shows the highest sensing response compared to other sensors, exhibiting a size-independent property for CO. Additionally, the response time of ZnO tetrapods modified by TiO2powder sensor is reduced. The improvement of the sensing properties is attributed to microstructure, lattice, surface area, and conductance modification of TiO2additive together with a high diffusion process deeply inside the sensing layer through the large pore size.