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

Abstract

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)0·35Cl0·20(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.