Enhanced H₂ sensing performance of perforated 3D NiO nanostructures and their comparative study with green synthesized NiO nanoparticles

In this work, perforated 3D NiO nanostructures have been synthesized by polyol method and their H₂ gas sensing performance was studied. To understand H₂ sensing performance of 3D perforated NiO nanostructures, it is compared with green synthesized NiO (GNiO) and Polyol-assisted hydrothermal synthesized (HSNiO) NiO nanostructures. Green synthesis method resulted in nanoparticle morphology, polyol-assisted hydrothermal method as 3D microsphere, and polyol method gave perforated 3D microspheres. XRD shows polycrystalline nature of NiO with grain size 15 – 22 nm. BET surface analysis clearly depicts that surface area of perforated 3D nanostructures (SNiO) is twice and thrice than HSNiO and GNiO nanostructures. XPS analysis confirmed the presence of Ni³⁺/Ni²⁺, high adsorption of O⁻, and oxygen vacancies due to high surface area. All three nanostructures were tested towards different H₂ gas concentrations resulted in 69%, 58% and 31% for SNiO, HSNiO and GNiO nanostructures for 100 ppm at 240 °C, respectively.