Highly Selective H₂S Gas Sensor Based on Ti₃C₂T MXene-Organic Composites

Area of Science:

• Materials Science
• Chemical Sensors
• Nanotechnology

Background:

• Effective hydrogen sulfide (H2S) sensors are vital for environmental and human health monitoring.
• Two-dimensional transition-metal carbides and nitrides (MXenes) show promise for gas sensing due to conductivity and surface functional groups.
• Previous MXene research focused on NH3 and VOCs, often with limited selectivity.

Purpose of the Study:

• To develop high-performance and cost-effective H2S sensors.
• To investigate the H2S sensing properties of pristine Ti3C2Tx and a novel composite with PDS-Cl.
• To elucidate the sensing mechanism and enhance selectivity for H2S detection.

Main Methods:

• Fabrication of pristine Ti3C2Tx thin films and Ti3C2Tx/PDS-Cl composites.
• Experimental gas sensing measurements for H2S at various concentrations.
• Density functional theory (DFT) calculations to understand sensing mechanisms and selectivity.

Main Results:

• Pristine Ti3C2Tx exhibited a negative response to H2S, unlike other tested gases.
• The Ti3C2Tx/PDS-Cl composite demonstrated a thirtyfold enhancement in H2S sensing response (2% at 5 ppm).
• A low limit of detection (LOD) of 500 ppb for H2S was achieved with high selectivity.

Conclusions:

• MXene-based composites, specifically Ti3C2Tx/PDS-Cl, are effective for selective H2S sensing.
• The study expands the application of MXenes to H2S detection and improves sensor performance.
• DFT calculations confirmed the importance of MXene surface functional groups in determining sensing mechanisms and selectivity.