Durian-like NiO architectures as an ultra-sensitive sensing materials for ammonia in normal temperature

Abstract Nanomaterials with hierarchical architectures have been an important topic for developing high-performance gas sensors. Here, durian-like nickel oxide (NiO) architectures, which are readily synthesized using nickel hydroxide as precursors, are for greatly enhanced ammonia detection at room temperature. The singular NiO architectures are assembled by nanoparticles with an approximate diameter of 2.3 µm and nanocones with an approximate length of 0.46 µm. A plausible growth mechanism based on particle-cone growth model is innovatively proposed and in which large-/small-dimension growth units composed of Ni(OH) 2 crystalline nuclei serve as building blocks. Gas sensing performances are investigated systematically at room temperature, the results indicate that change of resistivity of gas sensor based on durian-like NiO is more than 60% at ammonia concentration of 75 ppm. Moreover, the gas sensor also shows short response and recovery time and superior selectivity at the concentration of 50 ppm.