Selective detection of trimethylamine utilizing nanosheets assembled hierarchical WO2.9 nanostructure.

Sub-stoichiometric WO 2.9 has gained great attention in the field of gas sensor due to the appropriate oxygen vacancy. Herein, novel WO 2.9 hierarchical structures assembled by nanosheets are synthesized in large-scale through de-alloying the two-phase W/Cu pseudo alloy and then thermal annealing them in air ambient. During the growth process, Cu powder is introduced as host frameworks to support the hierarchical structure. By controlling the ratio of Cu and W powder, the diameters and the morphologies of microflowers can be precisely modulated. We compare the gas sensing characteristics of hierarchical W/WO 2.9 or WO 2.9 structure to trimethylamine (TMA) molecules with W/Cu ratios ranging from 1/9 to 9/1. Interestingly, the WO 2.9 sensor prepared with W/Cu ratio of 1/9 displays the best performance including highest response to TMA and rapidest response/recovery time, which are mainly due to its largest specific surface area and most energetic reaction sites. The selectivity and stability measurements further confirm the superior performances of WO 2.9 sensors to TMA and the excellent stability of the sensors. Our devices provide a facile and low cost way to fabricate high performance gas sensors which is strongly response to TMA. [Display omitted] • Novel oxygen-deficient WO 2.9 hierarchical structures assembled by nanosheets were reported. • WO 2.9 hierarchical structures were synthesized by the acid etching strategy with the two-phase W/Cu pseudo alloy as raw material. • WO 2.9 hierarchical structures with the W/Cu ratio of 1/9 exhibit excellent gas sensing properties to trimethylamine at 220 °C. • WO 2.9 hierarchical structures show high response of 95 to 50 ppm trimethylamine. • The superior gas sensing properties are mainly attributed to the high surface area and energetic reaction sites. [ABSTRACT FROM AUTHOR]