Highly sensitive, responsive, and selective iodine gas sensor fabricated using AgI-functionalized graphene

Area of Science:

• Materials Science
• Environmental Science
• Chemical Sensing

Background:

• Radioactive molecular iodine (I₂) is a hazardous volatile pollutant from nuclear energy applications.
• Effective detection of low I₂ concentrations is crucial for environmental and human health protection.

Purpose of the Study:

• To design and fabricate a novel sensing material for rapid and selective detection of molecular iodine (I₂) vapor.
• To investigate the sensing mechanism and performance of the developed material for real-world applications.

Main Methods:

• A three-component sensing material was synthesized using reduced graphene oxide (rGO), silver iodide (AgI) particles, and polystyrene sulfonate.
• The material's ability to reversibly adsorb and convert I₂ into polyiodides was studied.
• A sensor prototype was constructed and tested for response/recovery times and detection limits.

Main Results:

• The AgI particles facilitated I₂ conversion, inducing charge density variations in rGO for sensitive detection.
• The sensor achieved ultrafast response/recovery times (22/22 s dynamic, 4.2/11 s static) at room temperature.
• A detection limit of 25 ppb was achieved, surpassing OSHA and NIOSH standards and outperforming commercial sensors.

Conclusions:

• The developed rGO/AgI material demonstrates exceptional sensitivity, selectivity, and speed for I₂ detection.
• The sensor design offers a promising solution for real-time monitoring of radioactive iodine in nuclear applications.
• This research provides significant insights into designing advanced materials for volatile pollutant sensing.