Surface functionalization of porous In2O3 nanofibers with Zn nanoparticles for enhanced low-temperature NO2 sensing properties

Abstract

Different from the dominant method of surface modification of metal oxide sensing materials with noble metals, a simple and low-cost method is developed by using Zn nanoparticles as a surface modifier in this work. The first step involves the fabrication of porous In2O3 nanofibers by an electrospinning technique, and then Zn nanoparticles decorated In2O3 nanofibers are constructed by a simple thermal evaporation method. An increase in surface O2- species absorbing capability and a decrease in sensor resistance are observed by surface modification of In2O3 nanofibers with Zn nanoparticles. In comparison with pure In2O3 nanofibers, this kind of Zn–In2O3 composite nanofibers display higher response and better selectivity to NO2. The response of Zn–In2O3 nanofibers is up to 130.00–5 ppm NO2 at 50 °C, which is 13.7 times higher than that of pure In2O3. From our perspective, the improved NO2 sensing performances of Zn–In2O3 composite nanofibers are mainly attributed to the enhanced resistance modulation because of the formation of ohmic contacts between Zn nanoparticles and In2O3 nanoparticles.