3D porous p-n α-Fe2O3/NiO heteronanostructure for ultrasensitive H2S gas sensor

The porous p-n heterojunction nanocomposite is an important sensing material to enhance gas sensing performance by creating a cooperative effect at the formed interface within p-n junctions. In this paper, the 3D porous p-n α-Fe2O3/NiO heterojunction nanocomposite was prepared by a simple hydrothermal method, which was built by connecting numerous α-Fe2O3/NiO composite nanorods, nanoparticles and nanosheets. The formation of p-n heterojunctions between two oxides and the 3D porous nanostructure made this material show excellent gas sensing performance for H2S gas. The response of 5α-Fe2O3/NiO heteronanostructure sensor reached 239 for 20 ppm H2S at the optimum operating temperature of 300 °C. Additionally, it presented quick response-recovery times (38/35 s), high selectivity, long-term stability and ultra-low detection limit of 0.038 ppb. As a result, our work offers a simple method for creating 3D porous p-n α-Fe2O3/NiO heteronanostructure as a potential sensing material for detecting hydrogen sulfide.