Room temperature ppb level detection of chlorine using peripherally alkoxy substituted phthalocyanine/SWCNTs based chemiresistive sensors

Carbon nanotubes (CNTs) have created their niche in the area of gas sensing applications because of their unique mechanical and electronic properties. Their long recovery time and inadequate or temperature-based recovery result in substandard sensing properties. In this account, to overcome these issues and to highlight the application of CNTs in trace level identification and sensitive detection of chlorine (Cl2), operating at room temperature; a hybrid of single-walled carbon nanotubes anchored with peripheral alkoxy substituted phthalocyanine has been prepared. The as-prepared samples have been characterized for their morphological properties via transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), and structural properties via Raman, UV-vis, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS) techniques. Moreover, N2-adsorption analysis reveals that Brunauer-Emmett-Teller (BET) surface area for hybrid increases more than three-fold in comparison to SWCNTs-COOH. At room temperature, gas sensing properties of fabricated hybrid sensors exhibit remarkable Cl2 sensing characteristics with a limit of detection up to 1.33 ppb. Moreover, the nature of the interaction between hybrid sensors and gas analytes has been explored based on spectroscopic studies.