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

As a typical p-type semiconductor gas-sensing material, LaFeO3 has good response stability to H2S, but its responsiveness is low, and the detection limit is not low enough for large-scale use in the field of gas sensors. To obtain better performance, we synthesized Pd modified LaFeO3 using the sol–gel method. A total of 3 wt% of Pd–LaFeO3 with a high specific surface area had the highest response to H2S (36.29–1 ppm) at 120 °C, with relatively fast response–recovery times (19.62/15.22 s), and it had higher selectivity to H2S with other gases. Finally, we detected the H2S concentrations in the air around the shrimps, and the H2S concentrations that we obtained by the 3 wt% Pd–LaFeO3 in this study were within 10% of those obtained by GC–MS. According to the experimental results, noble-metal surface modification improves the performance of gas-sensing materials, and Pd–LaFeO3 has considerable potential in H2S detection.