NiO decorated CeO₂ nanostructures as room temperature isopropanol gas sensors

Abstract

Heterostructures developed using CeO₂ show promising peculiarities in the field of metal oxide gas sensors due to the great variations in the resistance during the adsorption and desorption processes. NiO decorated CeO₂ nanostructures (NiO/CeO₂) were synthesized <i>via</i> a facile two-step process. High resolution transmission electron microscopy (HRTEM) results revealed the perfect decoration of NiO on the CeO₂ surface. The porous nature of the NiO/CeO₂ sensor surface was confirmed from scanning electron microscopy (SEM) analysis. Gas sensing studies of pristine CeO₂ and NiO/CeO₂ sensors were performed under room conditions and enhanced gas sensing properties for the NiO/CeO₂ sensor towards isopropanol were observed. Decoration of NiO on the CeO₂ surface develops a built-in potential at the interface of NiO and CeO₂ which played a vital role in the superior sensing performance of the NiO/CeO₂ sensor. Sharp response and recovery times (15 s/19 s) were observed for the NiO/CeO₂ sensor towards 100 ppm isopropanol at room temperature. Long-term stability of the NiO/CeO₂ sensor was also studied and discussed. From all the results it is concluded that the decoration of NiO on the CeO₂ surface could significantly enhance the sensing performance and it has great advantages in designing best performing isopropanol gas sensors.