Enhancement of n-butanol sensing performance of porous ZnO flakes by decorating Ag nanoparticles

Abstract

This study designs to investigate a high-performance n-butanol gas sensor with a porous morphology. Porous ZnO flakes modified with Ag particles are prepared in two steps using hydrothermal and precipitation methods. Morphological analysis of the samples shows that the ZnO flakes were covered with mesopores with high porosity, and their edge lengths ranged from 3 μm to 6 μm, with a minimum thickness of 11.3 nm. Through rigorous gas sensing testing, we find that the optimal mass percentage Ag-ZnO sensor provided significantly better sensing behavior, with a 100.8 response for 100 ppm n-butanol, compared to 14.5 for the pure ZnO sensor, a 5.95-fold improvement. In addition, the sensor's optimal operating temperature is reduced from 290 °C to 190 °C, increasing its adaptability and versatility in practical applications. In subsequent tests, it is found that this Ag-ZnO sensor not only shows excellent selectivity to n-butanol but also favorable stability, with no significant degradation during 30 days of continuous testing. The experimental analysis shows that the formation of porous flake structure and the modification of Ag particles are effective approaches to improve the ZnO gas sensor.