Study of sensing mechanism of heterocyclic hazardous vapors with Metal Phthalocyanines

Industrial residues release harmful chemicals in the environment accruing toxicity in soil, air and hazard to mankind. Tetrahydrofuran (THF) and pyridine are common solvents utilized by chemical industries and research institutes. Low boiling point of these solvents amends their inhalation probability enhancing hazardous effects. Present study reports the fabrication of low power (1 V) driven chemresistors using organic dyes (Metal phthalocyanines (MPcs)) for the detection of industrial residues THF and pyridine. The variation in electrical signal of MPcs with exposure of reducing gases and tendency of THF and pyridine to donate lone pair's for charge transfer mechanism is utilized as detection principle. Aluminium Phthalocyanine hydroxide (AlPcOH), functionalized Copper and Nickel Phthalocyanines (CuPcS and NiPcS) and their various permuted combinations has been taken for sensing studies. It has been found that MPcs show higher responses towards pyridine (≈1571 times) under non-interfering and (≈169 times) at ambient conditions as compared to THF. For the case of THF, CuPcS-NiPcS composite has been found to exhibit maximum response and for pyridine CuPcS-AlPcOH-NiPcS composite exhibited maximum sensing response. AlPcOH has been found to decrease the recovery times of the composites, which is especially useful during pyridine sensing.