MOF-derived hierarchical hollow Fe2O3 nanobox functionalized with Ru doping for superior H2S sensing

The hierarchical Ru-Fe2O3 nanobox was prepared by a concise hydrothermal-annealing method. The resultant Ru-Fe2O3 was composed of small Fe2O3 nanoparticles with hollow and porous structures. In order to determine that Ru doping was a useful strategy to enhance the gas sensing performance of Fe2O3-based sensors, the sensing properties of all sensors were explored systematically. As a result, the sensor based on the Ru-Fe2O3 exhibited a higher response of 32.6–100 ppm of H2S at optimum temperature (200 °C), with a faster response-recovery speed (8/34 s), compared to the pure Fe2O3 sensor. In addition, the Ru-Fe2O3 sensor was able to monitor ppb amounts of H2S with high repeatability, good selectivity and excellent long-term stability. The hierarchical hollow microstructure and improved parameters (oxygen vacancy and crystal sizes) caused by the Ru doping were responsible for the enhancement of H2S sensing performance. Moreover, the sensing mechanism of Ru-Fe2O3 based sensor toward H2S has also been discussed clearly.