A room-temperature gas sensor based on 2D Ni-Co-Zn ternary oxide nanoflakes for selective and sensitive ammonia detection.

While most of the reports on NH gas sensors are either based on metal oxide composites with other 2D materials, polymers or noble metals or involve multi-step-based synthesis routes, this work is the first report on a pristine ternary metal oxide, 2D NiCoZnO nanoflake based room-temperature (RT) NH gas sensor. The 2D NiCoZnO nanoflakes were prepared by a one-step hydrothermal method. FESEM and TEM images displayed micro-flower like morphologies, containing vertically aligned interwoven porous 2D nanoflakes, whereas XPS and XRD data confirmed the successful growth of this ternary metal-oxide. This sensor revealed a good response, repeatability, linearity ( = 0.9976), a low detection limit of 3.024 ppb, and a response time of 74.84 s with excellent selectivity towards NH over six other VOCs. This improved performance of the sensor is ascribed to its large specific surface area (127.647 m g) resulting from the 2D nanoflake like structure, good electronic conductivity, variable valence states and abundant surface-active oxygen of NiCoZnO. Thus, this highly selective 2D NiCoZnO based RT NH gas sensor can be an attractive solution for the fabrication of next-generation NH gas sensors.