Urchin-like PdO–Fe2O3 heterojunctions for high-performance hydrogen sulfide gas sensors

To realize a synergistic effect between composition engineering and morphology modulation, PdO–Fe 2 O 3 heterojunction architectures with various morphologies were fabricated by facile hydrothermal and solution impregnation methods. Afterwards, gas sensing devices were constructed from the as-prepared PdO–Fe 2 O 3 composites, and their parameters were systematically investigated. The obtained results revealed that all PdO–Fe 2 O 3 sensors exhibited excellent selectivity properties and high responses to target gases. Importantly, an urchin-like PdO–Fe 2 O 3 sensing device produced the largest response of 75 to 50 ppm hydrogen sulfide at a PdO concentration of 4 wt%, which was approximately four times greater than that of a spherical PdO–Fe 2 O 3 sensor. The urchin-like sensor was also characterized by the highest response recovery efficiency, water resistance, and long-term stability. Furthermore, the sensing mechanism of the fabricated PdO–Fe 2 O 3 composite-based gas sensors was discussed comprehensively.