A ppb-Level Formaldehyde Gas Sensor Based on Rose-Like Nickel Oxide Nanoparticles Prepared Using Electrodeposition Process

In this study, rose-like nickel oxide nanoparticles (diameter of 400–500 nm) were prepared on indium tin oxide (ITO) glass substrates by a simple electrodeposition in NiSO 4 ⋅ 6H 2 O solution. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscope (TEM) were used for analysis of the NiO nanoparticles. The effects of operating temperature on the sensor response and the response versus gas concentration properties of the NiO nanorose-based sensors were investigated. We determined the operating temperature of the gas sensors to be 230 ∘ C, considering the proper sensitivity and a rapid response. In addition, gas-sensing characteristics of rose-like NiO nanoparticles to formaldehyde were investigated. It was shown that the sensors exhibited good response ( R g / R a = 3 . 4 3 ) properties to formaldehyde gas at 230 ∘ C, making them to be promising candidates for practical detectors to formaldehyde gas.