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-Fe 2 O 3 /NiO heterojunction nanocomposite was prepared by a simple hydrothermal method , which was built by connecting numerous α-Fe 2 O 3 /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 H 2 S gas. The response of 5α-Fe 2 O 3 /NiO heteronanostructure sensor reached 239 for 20 ppm H 2 S 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-Fe 2 O 3 /NiO heteronanostructure as a potential sensing material for detecting hydrogen sulfide . • The 3D porous p-n α-Fe 2 O 3 /NiO heteronanostructure has high specific surface area. • The 3D porous p-n 5α-Fe 2 O 3 /NiO heteronanostructure shows excellent detection of H 2 S. • The sensor presents fast response/recovery, high selectivity, low detection limit.