α-MoO3/TiO2 core/shell nanorods: Controlled-synthesis and low-temperature gas sensing properties

Abstract Crystalline α-MoO 3 /TiO 2 core/shell nanorods are fabricated by a hydrothermal method and subsequent annealing processes under H 2 /Ar flow and in the ambient atmosphere. The shell layer is composed of crystalline TiO 2 particles with a diameter of 2–6 nm, and its thickness can be easily controlled in the range of 15–45 nm. The core/shell nanorods show enhanced sensing properties to ethanol vapor compared to bare α-MoO 3 nanorods. The sensing mechanism is different from that of other one-dimensional metal oxide core/shell nanostructures due to very weak response of TiO 2 nanoparticles to ethanol. The enhanced sensing properties can be explained by the change of type II heterojunction barrier formed at the interface between α-MoO 3 and TiO 2 in the different gas atmosphere. The present results demonstrate a novel sensing mechanism available for gas sensors with high performance.

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