Insights into dehydration of layered cobalt hydroxide for gas sensor application with low-temperature response behavior

Dehydration of layer metal hydroxides at controlled annealing temperatures is an efficient strategy for regulating the material properties. In this work, we studied the dehydration process of α-Co(OH)₂ with flower-like nanostructure under various conditions and explored their gas sensing application. Stable dehydrated α-Co(OH)₂ obtained by solidification in air at 140 °C, exhibits specific selective low-temperature gas-sensing behavior for Et₃N. The response to 50 ppm Et₃N was up to 9.52 at 140 °C operating temperature with short response and recovery time. The sensor is the high reversibility and the excellent reproducibility with ppb level detection limit. The partial oxidation of the dehydration α-Co(OH)₂ in the air has a significant impact on the sensing performance. The large specific surface area of the dehydration α-Co(OH)₂ affords rich reactive sites for both reaction and adsorption of Et₃N molecules. This research provides a new solution for building low-temperature high-performance amine sensor.