Development of co(Oh)_xf_2−x nanosheets for acetone gas sensor applications: Material characterization and sensor performance evaluation

This study reports the employment of Co(OH)_xF_2−x nanosheets, a new material in the sensor field, for gas sensor applications. We synthesize Co(OH)_xF_2−x nanosheets via a hydrothermal route using SiO₂ sphere templates. Our material characterization confirms that the material is a densely clustered Co(OH)_xF_2−x nanosheet with an amorphous microstructure with some short-range ordering. Sensors based on the nanosheets demonstrate a high response of 269% toward 4.5 ppm of acetone gas at an operation temperature of 200^◦C and a very low minimum detection limit of 40 ppb. It functions effectively up to a temperature below 300^◦C, above which F is found to start to evaporate. Our discussion suggests that an excellent sensor performance arises from the high catalytic function of F incorporated in a high concentration in the material as well as the high specific surface area due to the morphology of densely clustered nanosheets.