A covalent organic polymer as an efficient chemosensor for highly selective H₂S detection through proton conduction

Area of Science:

• Materials Science
• Chemical Sensing
• Polymer Chemistry

Background:

• Covalent organic polymers (COPs) offer tunable properties for various applications.
• Developing selective and sensitive chemosensors for toxic gases like hydrogen sulfide (H₂S) is crucial for environmental and safety monitoring.
• Proton conduction mechanisms are being explored for efficient gas sensing applications.

Purpose of the Study:

• To synthesize a hydrazide-based covalent organic polymer (COP) functionalized with pyridine.
• To fabricate and evaluate an efficient chemosensor using the synthesized COP for detecting gaseous hydrogen sulfide (H₂S).
• To investigate the gas sensing performance, including response/recovery times and selectivity, of the COP-based sensor.

Main Methods:

• Synthesis of a hydrazide-based covalent organic polymer (COP) incorporating pyridine functionalities.
• Fabrication of a chemosensor device using the synthesized COP.
• Gas sensing measurements conducted in a dynamic flow-through resistance system at 25 °C.
• Evaluation of sensor response, recovery time, and selectivity towards H₂S against other gases (CO₂, NH₃, CO, NO₂).

Main Results:

• The synthesized COP-based chemosensor demonstrated efficient detection of gaseous H₂S.
• The sensor exhibited a rapid response time of 9 seconds and a recovery time of 12 seconds at 200 ppm H₂S and 25 °C.
• The chemosensor showed high selectivity for H₂S gas over other tested gases, including CO₂, NH₃, CO, and NO₂.

Conclusions:

• The developed hydrazide-based COP with pyridine functionalities is a promising material for fabricating highly efficient H₂S chemosensors.
• The proton conduction mechanism facilitates rapid and selective detection of hydrogen sulfide gas.
• The COP-based sensor offers a viable solution for real-time monitoring of H₂S in various environments.