Modification of Bi2O3 on ZnO porous nanosheets-assembled architecture for ultrafast detection of TEA with high sensitivity

Abstract

With the growing concern on environment protection, fast and selective detection of various harmful gases with the sensors based on metal oxide semiconductor (MOS) has stimulated increasing interest. However, the unsatisfied gas sensing performance of pure MOS hinders its practical application. In this paper, we propose a Bi2O3-ZnO heterojunction strategy to upgrade the performance of ZnO sensor to realize ultrafast detection of triethylamine (TEA) with high sensitivity and selectivity. To expound it, nanoscale Bi2O3-ZnO p-n heterojunctions were uniformly modified on the ZnO porous nanosheets-assembled architecture (PNSA) via an impregnation, freeze-drying and calcination method by using self-made Zn5(CO3)2(OH)6 as precursor. The obtained Bi2O3/ZnO PNSAs are about 7 µm in size, in which the thickness of porous nanosheets is around 25–38 nm. Impressively, compared with the sensor based on pure ZnO PNSA, the Bi2O3/ZnO PNSA sensor exhibited remarkably boosted triethylamine (TEA) sensitive performances, especially of faster response speed (<1 s for 100 ppm TEA), better selectivity (STEA/toluene = 406.013) and higher sensitivity (26.886/ppm for 1–100 ppm TEA). The sensitization mechanisms of Bi2O3-ZnO heterojunction on ZnO PNSAs was discussed in detail.