Stable Cobalt Porphyirn Ometed Type Small Molecule Sensor for the Sensitive and Selective Detection of Ammonia Gas at Room Temperature

Abstract

AbstractThe ammonia (NH3) gas device sensors at room temperature rapid‐response (RTRR) selective discovery is a challenging and massive task that is restricted due to reduced room‐temperature (RT) detecting materials and their unsatisfactory gas detecting performance features. In this work, an organic small molecule 5, 10, 15, 20‐tetrakis {4‐[N,N‐di(4‐methoxyphenyl) amino‐phenyl]‐porphyrin (PO) and its cobalt complex cobalt‐porphyrin (PCo) based twisted type structure sensor is established for the detection of NH3 gas at RT. Interestingly, the introduction of Co atom into porphyin ring center increases overall performance, including high stability maximum response of 85% to 20 ppm NH3, and high selectivity towards ammonia compared to PO molecule. In terms of selectivity, the PCo sensor has a great affinity for NH3 due to the unpaired electron in dx2‐y2 with the porphyrin‐system, which boosts NH3 selectivity even in a mixture of gases. The detection range is 1 ppm, which is an 11% response with outstanding fast response (180 s) and recovery (10 s) containing excellent reproducibility to 20 ppm NH3. The superior gas‐detecting characteristics of PCo are ascribed to the interface between NH3 and cobalt Co‐group of PCo. The results from sequential studies deliver a novel approach and procedure for exploring RT ammonia gas device sensors.