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 via 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.