Hydrothermal synthesis of Ag modified ZnO nanorods and their enhanced ethanol-sensing properties

Silver (Ag) nanoparticles decorated zinc oxide (ZnO) nanorods were synthesized by a simple hydrothermal treatment for enhancing gas-sensing performance toward ethanol. The X-ray diffraction (XRD) and energy dispersive X-ray spectroscopic (EDS) results indicate the presence of Ag nanoparticles. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results reveal that Ag nanoparticles are tightly anchored on the surface of ZnO nanorods. The UV-vis diffuse reflectance spectroscopy (UV-vis DRS) results confirm that the band gap energy is decreased due to the decoration of Ag. The gas sensing performance of as-synthesized materials was investigated at different working temperatures and toward various ethanol concentrations. The gas-sensing results exhibit that the 1 wt% Ag/ZnO sensor shows the highest sensitivity of 389.6 toward 800 ppm ethanol and fast response among all the sensors. The improved response of Ag/ZnO sensors is ascribed to the catalysis and spillover effect of Ag. This result makes Ag/ZnO sensor a very promising gas sensing material for gas detection.