Improvement of Gas Sensing of Uniform Ag₃PO₄ Nanoparticles to NH₃ under the Assistant of LED Lamp with Low Power Consumption at Room Temperature

Light-driven semiconductor gas sensors are attracting considerable research attention in the recent past. Among them, silver phosphate (Ag3PO4) material has excellent photocatalytic activities due to its high separation efficiency of electron-hole pairs under visible light. Inspired by the above point of view, in this study, Ag3PO4 nanoparticles were successfully synthesized via simple precipitation method. The microstructure of Ag3PO4 nanoparticles were characterized by scanning electron microscopy (SEM). The crystalline phase and the composition of the elements and the chemical bonding states of the material were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. Then the gas sensing performance of Ag3PO4 to ammonia (NH3) was systematically explored at room temperature under the illumination of LED lamp and the same was compared with the dark condition as well. Interestingly, the response value to NH3 under LED lamp was 30 % higher than that of dark condition and the detection limit was found to be as low as 10 ppm at room temperature. This can be ascribed to the generation of more oxygen species under visible light, which benefitted for enhancing the gas sensing performance of the sensor. Surprisingly, Ag3PO4 sensor exhibited superior selectivity to NH3 under mixed target gases, which can be attributed to the lone pair electrons of NH3 that tend to coordinate the empty orbitals of silver atom.