Loading uniform Ag3PO4 nanoparticles on 3D peony-like WO3 for good stability and excellent selectivity towards NH3 at room temperature

Abstract

Abstract Designing heterojunction structure is an extremely significant method to improve the properties of semiconductors in many research fields. This method is employed in the present study to promote the gas sensing performance of Ag3PO4 nanocomposites at room temperature (25 ℃). The nanocomposite of Ag3PO4 nanoparticles and three-dimensional peony-like WO3 (WO3/Ag3PO4) were successfully prepared by the precipitation method. The crystalline phases were analyzed by X-ray diffraction (XRD), and the microstructure was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The chemical bonding states were analyzed by X-ray photoelectron spectroscopy (XPS). The gas sensing performance of WO3/Ag3PO4 sensor was systematically explored at room temperature. The composite sensors possessed higher response and lower detection limit (1 ppm) to NH3 than the single kind of materials, which is ascribed to the synergistic effect achieved by designing heterojunction structure. Among the different composite sensors tested, A5W5 (mass ratio of Ag3PO4:WO3 was equal to 5:5) gas sensor displayed the highest response value to NH3 at room temperature. Interestingly, A5W5 gas sensor exhibited relatively good stability and excellent selectivity to NH3. Besides, A5W5 sensor displayed relatively good response under high humidity. Finally, the gas-sensing mechanism of WO3/Ag3PO4 sensor was explained in detail. Taken altogether, the as-prepared sensor is highly efficient in detecting NH3 and could be suitable for practical applications. In addition, this study also provided new method to develop Ag3PO4-based sensors in the gas-sensing field.