Optimization of metal nanoparticle amount on SnO2 nanowires to achieve superior gas sensing properties

SnO2 nanowires (NWs) functionalized with Ag nanoparticles (NPs) were tested for NO2 gas sensing ability; the results revealed a bell-shaped curve as a function of the surface coverage of Ag NPs. A model that can explain these experimental observations regarding the functionalization of metal NPs on oxide NWs, which is the most widely used approach for improving the sensing capabilities of NWs, was proposed and validated. Based on the electronic and chemical sensitizations of metal NPs, a mathematical equation was formulated to predict the optimal surface coverage of metal NPs on the NWs to obtain maximum sensing performance. This study may provide new insight and guidelines for the development of highly sensitive NW-based gas sensors. (C) 2016 Elsevier B.V. All rights reserved.