A nanoscale sensing material was prepared in a facile manner via the phase transition of wurtzite CoO to spinel Co₃O₄, as a new gas sensor preparation platform. The combination of a h-CoO → β-Co(OH)₂ phase transition followed by thermal oxidation led to the spontaneous deposition of Co₃O₄ on interdigitated electrodes. The prepared Co₃O₄ nanoplates exhibited good contact adhesion with the sensor substrate, which obviated the need for conventional film forming processes, and were shown to be suitable for direct gas sensing. Compared to other Co₃O₄ sensors, the phase-transitioned Co₃O₄ nanoplates showed very high sensitivity to acetone gas (12.5 for 1 ppm acetone) in the range 20–1000 ppb at an operating temperature of 200 ℃ and enhanced selectivity. The improved performance of the Co₃O₄ nanoplates was attributed to typical crystal facets with mainly exposed (111) planes as well as an enlarged surface area during phase transition. Therefore, it was concluded that phase transition methods can be applied to promising sensing substances to develop a variety of related ultrasensitive acetone sensors.

通过纤锌矿CoO到尖晶石Co ₃ O ₄的相变，以一种简便的方式制备了纳米级传感材料，作为一种新型的气体传感器制备平台。h-CoO→β-Co（OH）₂相变和热氧化的结合导致Co ₃ O ₄在指叉电极上自发沉积。制备的Co ₃ O ₄纳米板与传感器基板表现出良好的接触粘附性，从而避免了对常规膜形成工艺的需求，并被证明适用于直接气体传感。相较于其他Co ₃ O ₄传感器，相变Co ₃在200℃的工作温度下，O ₄纳米板对丙酮气体（在1 ppm丙酮中为12.5）具有很高的灵敏度，并且在200℃的工作温度下具有较高的选择性。Co ₃ O ₄纳米板性能的改善归因于典型的具有主要暴露（111）平面的晶面以及相变过程中增大的表面积。因此，可以得出结论，相变方法可以应用于有前景的传感物质，以开发各种相关的超灵敏丙酮传感器。