Regulating Co-MOF array films to construct Co3O4 in-situ sensors for ultrasensitive and highly selective triethylamine detection

Sensing films with controllable thickness and open-space array structures are desperately desired for practical application. In addition, in-situ gas sensors based on MOFs-derived MOSs films have been rarely reported. Herein, a room-temperature growth approach was proposed to fast prepare controlled Co-MOF arrays films on the substrates with interdigital electrodes. The as-prepared precursor films were further annealed to obtain Co3O4 in-situ sensors. This work systematically investigated the morphologies, structures, contact characteristics, and oxygen species of sensing films. It was found that they have apparent effects on the triethylamine sensing behaviors, thus obtaining the optimized gas sensor. The sensor exhibited excellent sensing performance, including fast response (from 82 s to 9 s), high sensitivity (Rg/Ra=230), and improved selectivity, compared to the Co3O4 sensor derived from non-MOF precursor films. The excellent triethylamine sensing performance benefited from the abundant oxygen vacancies and conducting channels. This work provides a simply-effective strategy for large-scale fabrication of in-situ gas sensors.