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.