Synthesis Of Porous Co₃O₄ Nanorods Via CoC₂O₄·H₂O Precursor And Gas Sensoring Property Research

Cobalt oxide is an important semiconductor P-type transition metal oxides and its crystal structure is cubic spinel structure type with Fe3O4 as allomerism. Different micro structures (grain radius, pore size distribution) of Co3O4, its physical and chemical properties are also very different. In this paper, we manufacture porous Co3O4 nanorods via the cobalt oxalate precursor prepared in situ decomposition, while we also research the effect of the different of growth concentration, growth time and the decomposition temperature on the final product morphology. We find that suitable growth liquid concentration is conducive to the growth of uniform, large aspect ratio of cobalt oxalate nanorods. And the extension of reaction time, make the diameter of nanorods COC2O4· 2H2O generated becomes small. The decomposition temperature has great effect on the porous structure of the product, when the decomposition temperature of 350 ℃, for there are a lot of big holes obtained on the Co3O4 nanorods. These large holes are evenly distributed on the nanorods, wtih size uniform, uniform dispersion, at the same time there still exist nanoporous between nanoparticles, and the nanorods is entire through-hole structure.Currently, many studies show that high sensitivity of the sensor is no longer a problem, but the sensor’s real-time quick monitoring there is still a challenge. In order to overcome the metal oxide semiconductor porous structure such as a closed hole, the accumulation hole disabled the rapid response and recovery of the gas sensors. This paper was prepared for the rapid response and recovery of the semiconductor-type gas sensors for real-time monitoring, mainly studied the gas sensing performance of the Co3O4 sample prepared by hydro thermal method prepared COC2O4·2H2O precursor annealing. Gas Sensing test results show that the porous cobalt oxide nanorods can be quickly in less than 3 s time to 100 ppm in the concentration of ethanol gas response and recovery. Its intrinsic mechanism analysis shows that the rich pore structure and proper links between particles is good for the electrical signal transmission and the target gas diffusion; higher specific surface area is more advantageous to the target gas adsorption on the material so as to achieve a higher sensitivity. At the same time, comparative study in this paper shows that the bigger the specific surface area of the material, the higher the sensitivity to ethanol; the richer holes of the material and the greater the diameter of the hole, the shorter of the response and recovery time.