Controllable synthesis of porous Co3O4 nanorods and their ethanol-sensing performance

A simple strategy for synthesizing porous Co₃O₄ nanostructures through a hydrothermal process with subsequent thermal decomposition of the obtained Co(CO3)0·35Cl0·20(OH)1.10 precursors was introduced. To understand the growth mechanism of the Co(CO₃)_0·35Cl_0·20(OH)_1.10 precursors and realize morphology control of the resultant Co₃O₄ nanomaterials, a series of controlled experiments were carried out by varying CO(NH₂)₂ dosages, hydrothermal temperatures and time. The Co₃O₄ nanorods obtained under optimized synthesis conditions demonstrated porous structural features, which were constructed by well-connected nanograins, leaving many pores composed of the space between nanograins. The ethanol-sensing behaviors of these Co₃O₄ nanostructures were evaluated, showing the highest response (19.581) and a short response and recovery time (1 s/10 s) to 100 ppm ethanol. Moreover, the Co₃O₄ sensor demonstrated excellent anti-interference ability toward several interfering gases such as methanol, benzene hexane, and dichloromethane. The stability of the Co₃O₄ sensor was further confirmed by 14 days of continuous testing. Compared with previously reported works, this Co₃O₄ sensor still demonstrated outstanding gas sensing properties due to its unique advantages such as 1D porous nanostructures, high BET surface area, abundant oxygen vacancies, and active cobalt sites.