Highly Sensitive and Selective NH3 Sensor Based on Au Nanoparticle Loaded MoO3 Nanorods

MoO ₃ is favored by scholars for its satisfactory gas-sensitive performance, and has made outstanding achievements in the detection of NH ₃ . In this paper, MoO ₃ nanorods are loaded with Au to obtain Au@MoO ₃ , in order to further improve the gas sensitivity. By means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and X-ray photoelectron spectra (XPS), it is confirmed that Au nanoparticles are successfully modified on MoO ₃ nanorods. The Au nanoparticles with the diameter of about 20-40 nm are uniformly dispersed on the surface of the nanorods with the diameter of about 100-200 nm. Gas sensitivity test results show that Au@MoO ₃ has excellent sensitivity to NH ₃ , and strong anti-interference to other gases, with outstanding selectivity. The response of Au@MoO ₃ to 100 ppm NH ₃ at the optimum operating temperature of 370 °C is as high as 882.5, moreover, it can detect NH ₃ as low as 1 ppm (response 8.6). Compared with pure MoO ₃ nanorods, the sensitivity is improved and the operating temperature is reduced. The sensitive mechanism of Au@MoO ₃ is also discussed.