Bismuth tungstate nanosheets sensors based on Temkin adsorption model for triethylamine detection

Abstract

Nanostructured Bi₂WO₆ and Bi₂W₂O₉ were synthesized using a hydrothermal method. The crystal structure, morphology, and specific surface area were analyzed via X-ray diffraction, scanning electron microscopy, Brunauer–Emmett–Teller and X-ray photoelectron spectroscopy (XPS) analysis, respectively. The characterization results show that Bi₂WO₆ has a higher specific surface area and a larger pore size than Bi₂W₂O₉, which promote oxygen adsorption and surface reactions. Gas-sensitive tests show that both sensors have a lower detection limit of 2.5 ppm as well as short response and recovery times for detecting triethylamine (TEA). They also have excellent cycling and long-term stability at 180 °C and exhibit excellent gas-sensing performance. The Bi₂WO₆ sensor has a higher response and sensitivity, as well as better selectivity, than the Bi₂W₂O₉ sensor, which is related to the uniformly layered structure of the former material. We have analyzed the mechanism that enables these sensors to detect TEA and have used the Temkin adsorption model to explain the linear relationship. We find that this model provides an excellent theoretical foundation for fitting the working curve of these semiconductor sensors.