Green Mediated Synthesis of Macroporous Hierarchical CeO2 Nanoparticles using Mimosa pudica Leaf Extract for Humidity Sensing Application

Abstract

Metal oxide nanoparticles are popular candidates for chemiresistive sensors application. Cerium oxide (CeO₂) based semiconducting gas sensors have gained rapid interest in recent years. In this study, an environment-friendly green synthesis approach was employed for the synthesis of macroporous CeO₂ nanoparticles using Mimosa pudica leaf extract. Later the performance of CeO₂ nanoparticles for humidity sensor is demonstrated. X-ray diffraction studies revealed the cubic fluorite crystal structure with no impurities, scanning electron microscopy analysis revealed the macroporous morphology of CeO₂ hierarchical nanoparticles. Humidity sensing properties were studied using interdigitated electrode coated with CeO₂ nanoparticles. The results showed the sensing response of 0.5 times for 10% RH (relative humidity) and seven times for 90% RH. The response and recovery times were found to be as low as 12 s and 15 s, respectively. The experimental results provided an environment-friendly approach for the synthesis of CeO₂ particles and revealed promising results in humidity sensing application.