Structural evolution of NiO from porous nanorods to coral-like nanochains with enhanced methane sensing performance

Abstract The microstructure of metal oxide semiconductor (MOS) plays an important role in improving its gas-sensing performance. In this work, in order to investigate the influence of structural modification on gas-sensing characteristics, two NiO nanostructure, including porous nanorods (PNRs) and coral-like nanochains (CNCs), were prepared via annealing pre-synthesized NiC2O4 nanorods at different temperatures and employed as methane (CH4) sensing materials. The as-obtained NiO nanorods at 370 °C exhibit a porous structure with a large specific surface area of 225.05 m2/g. While, the NiO nanochains consisted of many nanoparticles with the size of 28 nm can be synthesized at 450 °C. Despite the slight decrease in the specific surface area of NiO nanochains, the methane sensing properties were remarkably enhanced compared to that of NiO nanorods. The enhanced methane sensing performance of NiO was discussed from the perspective of structure evolution from nanorods to nanochains.