Ag decorated ZnO nanocrystallines synthesized by a low-temperature solvothermal method and their application for high response H_2 gas sensor

摘要

Different ratios (0, 1 and 3 mol%) of Ag decorated ZnO nanocrystallines are prepared via a simple low-temperature solvothermal method. The characterization results show that the as-prepared products are composed of numerous small nanocrystallines with irregular shapes. XPS analysis reveals the adsorbed oxygen on the surface of ZnO, which can react with the detected gas molecules and improve the sensor response. The gas-sensing properties of the sensors made from the Ag-decorated ZnO nanocrystallines are tested for hydrogen detection at 260 ℃. The results show that the sensor made from 1 mol% Ag-decorated ZnO nanocrystallines exhibits excellent gas-sensing properties, demonstrating a high gas response of 59.35 toward 3000 ppm hydrogen, a fast response time (5 s) and recovery time (6 s) (with 1000 ppm hydrogen), good repeatability and stability. The improved hydrogen sensing properties can be attributed to the catalytic effect of Ag nanoparticles, which offer more active sites for the reaction and facilitate the adsorption and desorption of hydrogen on the surface of ZnO nanocrystallines.