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

Abstract

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.