Design and fabrication of capacitive nanosensor based on MOF nanoparticles as sensing layer for VOCs detection

Due to high porosity and increased surface area; metal organic frameworks (MOFs) have been widely used in gas storage applications as well as volatile organic compounds (VOCs) detection. Most of these sensors are electromechanical or electrochemical based; however there are few works in which capacitive sensors were developed using micrometer MOFs. In the present study, for the first time, MOF (Cu-BTC) nanoparticles were used to develop capacitive sensor device for detecting VOCs (e.g. methanol, ethanol, isopropanol, and acetone). The studied capacitive sensors were performed in a moderate environment (10% relative humidity and 25 °C). Capacitive sensors were fabricated in a sandwich form or parallel plate by using copper plate as a back electrode, MOF nanoparticles layer as the dielectric, and interconnected silver spots as the upper electrode of the capacitor. Linearity of the response versus LCR meter frequency, reusability, reversibility, response time, and limit of detection (LOD) of the capacitive sensor were determined to evaluate the sensor performance. The results showed high ability of Cu-BTC nanoparticles synthesized as dielectric layer of a capacitive nanosensor to determine VOCs.