Heterojunctions are very promising structures due to their hybrid properties, which are usually obtained via a multistep growth process. However, in this paper, WO-WO heterostructures are synthesized via a novel one-step approach by using isopropanol as reaction media and are applied in NH gas detection for the first time. The obtained WO-WO heterostructures with loose nanowire bundle-like morphology show a response value of 23.3 toward 500 ppm NH at 250 °C, which is 5.63 times higher than that of pristine WO. In addition, the WO-WO sensor also exhibits great dynamic response/recovery characteristics (13 s/49 s @ 500 ppm NH), superb selectivity and low detection limit of 460 ppb. The substantial improvement in the response of WO-WO heterostructures toward NH can be explained by the formation of n-WO/n-WO heterojunctions that facilitate the generation of a more extended depletion layer as well as the enhancement of specific surface area and pore volume. Our research results open an easy pathway for facile one-step preparation of heterojunctions with high response and low cost, which can be used for the development of other high-performance gas sensors.
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http://dx.doi.org/10.1016/j.jhazmat.2018.04.020 | DOI Listing |
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