Development of Ag/ZnO nanorods and nanoplates at low hydrothermal temperature and time for acetone sensing application: an insight into spillover mechanism

Abstract

Nanostructure synthesis at low temperature with high purity and yield has a great potential in the present competitive research and development of nanomaterials for varieties of application. Here, we demonstrate the facile hydrothermal synthesis of ZnO nanocomposites at low hydrothermal temperature and time. With barely 80 °C hydrothermal temperature and 2 h of reaction time, ZnO nanorods were successfully synthesized, while by slightly increasing the reaction time (6 h-and-on), nanoplates of the same material were developed. Both the obtained nanostructures were analyzed using physio-chemical characterizing tools and examined for practical relevance as gas sensing material. The optimized sample was further treated to Ag loading (1–5 mol%) for lowering the operating temperature of the sensor. ZnO sample with 3 mol% Ag loading showed excellent sensitivity of 92.7% for 1000 ppm of acetone concentration with a drop in the operating temperature from 325 °C (Pristine ZnO) to 250 °C (Ag-loaded ZnO). The morphological correlation with reaction time and thereby sensitivity and spillover mechanism are discussed.