Perforated Co3O4 nanoneedles assembled in chrysanthemum-like Co3O4 structures for ultra-high sensitive hydrazine chemical sensor

Herein, we report the successful synthesis of chrysanthemum-like Co3O4 structures composed of high-aspect ratio perforated Co3O4 nanoneedles. The chrysanthemum-like Co3O4 structures were obtained by the heat treatment of cobalt-carbonate-hydroxide (Co(CO3)0.5(OH)·0.11H2O) chrysanthemum structures which were prepared by simple and facile hydrothermal process. The prepared materials were characterized using several techniques which confirmed that the prepared materials, i.e. precursor Co(CO3)0.5(OH)·0.11H2O and Co3O4, both possess chrysanthemum-like morphologies which are made by the accumulation of radially oriented nanoneedles. The prepared chrysanthemum-like Co3O4 structures were further used as electron mediators to fabricate highly sensitive and selective hydrazine (N2H4) chemical sensors. The sensitivity, detection limit, linear range, selectivity, repeatability, and reproducibility of such fabricated chrysanthemum-like Co3O4 structures base hydrazine chemical sensor was comprehensively investigated. It was observed that the sensing of the fabricated sensors are highly dependent on the morphology of Co3O4, and the chrysanthemum-like Co3O4 structures exhibited the best sensing performance. Further, a good repeatability and reproducibility, longtime stability and great selectivity both in amperometric and voltammetric chrysanthemum-like Co3O4 structures based sensors were observed. The detailed sensing results confirmed that the fabricated chemical sensor exhibited a high sensitivity of 107.9 μA mM−1, a detection limit of 3.7 μM and a linear range of 50-1088 μM. The observed results demonstrate that the synthesized chrysanthemum-like Co3O4 offers a promising probe candidate for the fabrication of highly sensitive and selective chemical sensors.