Synergistic H₂S sensing in Pd-functionalized In₂S₃flakes

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Hydrogen sulfide (H2S) is toxic and corrosive, necessitating reliable sensors for safety and environmental monitoring.
• Indium sulfide (In2S3) offers potential for gas sensing due to its porous microstructure and active sites.

Purpose of the Study:

• To develop a high-performance chemiresistive H2S gas sensor.
• To enhance the sensing capabilities of In2S3 using palladium (Pd) nanoparticle functionalization.

Main Methods:

• Chemical vapor deposition (CVD) was used to grow In2S3 flakes.
• Pd nanoparticles were synthesized and decorated onto the In2S3 flakes.
• Gas sensing performance was evaluated at various H2S concentrations and temperatures.
• Density functional theory (DFT) calculations were performed to understand the sensing mechanism.

Main Results:

• The Pd-functionalized In2S3 sensor exhibited a 1.4-fold increase in response and enhanced selectivity towards H2S.
• A sensing response of ~67.60% was achieved at 50 ppm H2S at 75 °C.
• The sensor demonstrated rapid kinetics (48s response, 260s recovery) and a low limit of detection (LOD) of 59 ppb.
• High humidity tolerance (up to 80% RH) and excellent repeatability were observed.
• DFT calculations revealed an 8-fold increase in adsorption energy and significant charge transfer upon Pd decoration.

Conclusions:

• Pd nanoparticle functionalization significantly enhances the performance of In2S3-based H2S sensors.
• The developed sensor offers a practical and efficient solution for H2S detection.
• First-principles calculations provide insights into the electronic sensitization mechanism responsible for ppb-level sensitivity.