A Highly Sensitive and Flexible Metal-Organic Framework Polymer-Based H₂S Gas Sensor.

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Hydrogen sulfide (H2S) is a toxic gas requiring sensitive and selective detection methods.
• Existing H2S sensors often face limitations in sensitivity, response time, or operational conditions.
• Flexible and low-power sensors are needed for portable environmental monitoring applications.

Purpose of the Study:

• To fabricate a novel metal-organic framework (MOF)-polymer mixed-matrix flexible membrane for H2S gas detection.
• To investigate the effect of ionic liquid (IL) concentration on the conductivity and performance of the sensor.
• To evaluate the H2S sensing properties, including sensitivity, selectivity, response/recovery times, and stability.

Main Methods:

• Fabrication of a flexible membrane by embedding MOF-5 microparticles into a conductivity-controlled chitosan (CS) matrix blended with glycerol ionic liquid (IL).
• Characterization of the MOF-5/CS/IL composite membrane.
• Testing of the gas sensor's performance for H2S detection at room temperature, varying H2S concentrations.

Main Results:

• The MOF-5/CS/IL sensor exhibited high sensitivity to H2S gas, detecting concentrations as low as 1 ppm at room temperature.
• The sensor demonstrated excellent selectivity, a fast response time (<8 s), and a recovery time (<30 s).
• Outstanding sensing stability was achieved, with an average detection rate of 97% for 50 ppm H2S.

Conclusions:

• The developed MOF-5/CS/IL flexible membrane sensor is a high-performance device for H2S gas detection.
• The sensor's properties, including high sensitivity, low-power consumption, and flexibility, make it suitable for environmental sustainability applications.
• This novel composite material offers a promising solution for real-time, on-site H2S monitoring.