Corn stigma template-assisted synthesis of single crystal MoO₃ elliptical nanosheets for chemiresistive detection of dibutylamine vapor

The fabrication of chemoresistive sensor for the sensing detection of hazardous organoamines has recently aroused wide interest. However, there is no report on dibutylamine (DBA) to date. For this aim, two MoO₃ materials were simply prepared by calcining corn stigma bio-template immersed in ammonium molybdate solution. Among, MoO₃-600 hierarchical structure calcined at 600 °C is cross-linked by relatively homogeneous elliptical nanosheets, which has single crystal nature, uniform mesopores and narrow bandgap, as well as oxygen vacancy defects induced by Mo⁵⁺. The synergism of above advantageous elements not only promotes the quick migration of gas molecules and their adsorption behavior on sensing layer, but also improves the conductivity of sensing material and content of surface adsorbed oxygen. Accordingly, under the catalysis of dangled bonds for surface Mo⁶⁺ ions, MoO₃-600 sensor firstly realizes rapidly sensitive and selective detection of trace DBA. At 170 °C, its response value reaches up to 254.8 for 100 ppm DBA with fast response time of 4.4 s. It also exhibits low detection limit, good stability and humidity tolerance, along with satisfactory practical detection to atrazine and carbosulfan. Besides, related sensing mechanism to DBA vapor is still analyzed in detail.