Investigating the Role of Amide to Thioamide Substitution of a Covalent Organic Polymer for the Selective Chemodetection of H₂S at Room Temperature

Hydrogen sulfide (H 2 S) sensors are in high demand for diagnosing metabolic diseases and monitoring environmental pollution. Nowadays, covalent organic polymers (COPs) have gained significant attention in gas sensing due their unique properties, such as high surface area, porous behavior, and proton conduction. Herein, we have demonstrated a solvent-free mechanochemical method for synthesizing an amide-based covalent organic polymer (COPO). Further, we treated COPO with Lawesson’s reagent to synthesize a thioamide-based covalent organic polymer (COPS). The synthesized COPs have been fabricated as a material for recognizing H 2 S. The COPO sensor shows a 2.6-fold enhanced response of 190% toward 100 ppm of H 2 S, with a rapid response/recovery time of 20/40 s at 25 °C, compared to COPS (73%). Moreover, COPO exhibits adequate selectivity to H 2 S, complete recoverability, good repeatability, and long-term stability. These results offer a contemporary approach for the real-time monitoring of H 2 S at room temperature.