Pd-Modified LaFeO₃ as a High-Efficiency Gas-Sensing Material for H₂S Gas Detection

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Lanthanum ferrite (LaFeO3) is a p-type semiconductor with stable response to hydrogen sulfide (H2S).
• However, its low responsiveness and high detection limit hinder large-scale application in gas sensors.
• Enhancing LaFeO3 performance is crucial for effective H2S monitoring.

Purpose of the Study:

• To improve the gas-sensing performance of LaFeO3 for H2S detection.
• To synthesize and characterize palladium (Pd)-modified LaFeO3.
• To evaluate the H2S sensing properties of the modified material.

Main Methods:

• Sol-gel method was employed for the synthesis of Pd-modified LaFeO3.
• Gas sensing performance was tested at various temperatures, focusing on 120 °C.
• Selectivity was assessed against common interfering gases.
• Real-world H2S detection was performed in shrimp environments and compared with Gas Chromatography-Mass Spectrometry (GC-MS).

Main Results:

• 3 wt% Pd-LaFeO3 exhibited the highest response to 1 ppm H2S (36.29) at 120 °C.
• The Pd-modified material showed fast response (19.62 s) and recovery (15.22 s) times.
• Enhanced selectivity towards H2S over other gases was observed.
• Real-world H2S concentration measurements using 3 wt% Pd-LaFeO3 showed less than 10% deviation from GC-MS results.

Conclusions:

• Noble metal surface modification, specifically with Pd, effectively enhances the gas-sensing performance of LaFeO3.
• Pd-LaFeO3 demonstrates significant potential as a sensitive and selective material for H2S detection.
• The findings support the use of Pd-LaFeO3 in practical environmental monitoring and safety applications.