Biotemplate synthesis of single crystal MoO3 hierarchical tubules assembled from nano-rectangles for conductometric sensing of diisopropylamine vapor

The development of metal oxide-based gas sensors with high sensing to carcinogenic organoamines has recently attracted much attention. However, there is no related report on detecting diisopropylamine (DIPA). Herein, renewable poplar branches were selected as bio-template and immersed in ammonium molybdate solution. Subsequently, the above precursors were calcined in air to successfully synthesize two types of MoO3 nano-rectangles with different sizes. Amongst, biomorphic MoO3-500 tubules cross-linked by relatively small nano-rectangles were simply replicated by calcining precursors at 500 °C, which have multistage pores and single-crystal nature. Such structure characteristics can facilitate the fast diffusion of target gas, and increase the conductivity, active sites, as well as content of adsorbed oxygen species in sensing material. Especially, under the synergism of surface unsaturated Mo6+ catalysis, we realized the conductometric detection of DIPA vapor by metal oxide-based sensor for the first time. At 170 °C, MoO3-500 sensor shows high response value (244) and fast response speed (4 s) to 100 ppm DIPA vapor. Meanwhile, it still presents low detection limit, good selectivity and stability. Therefore, MoO3-500 tubules are expected to be a promising material for accurately detecting trace DIPA vapor.