| Co3O4, as an important metal oxide ceramic material, has been widely applied in the scopes of magnetic semiconductors, gas sensors and lithium-ion cathode materials, and so on. At present, it has been aroused general interest that Co3O4 is used in the domain of supercapacitor. Meanwhile, there are a small amount of literatures that have reported Co3O4 has a good photocatalytic activity. In the application, the microstructure of Co3O4, such as size of crystal particles and crystal morphology, is a key parameter which can influence and determine its performance. In the paper, we summaried properties, applications and preparation of Co3O4. In addition, we prepared Co3O4 and its composite materials by different methods. By means of the relevant analysis and testing technology, crystal structure and morphology of the materials were analyzed. Moreover, catalytic, photocatalytic and electrochemical properties of Co3O4 and its composite materials were mainly investigated. The main details are as follows:1. With sodium hexametaphosphate as the inorganic crystal structure directing agent, the precursor of Co3O4 was obtained by the method of simple liquid precipitation. Then Co3O4 particles were gotten by calcining the precursor. The performance of decomposition of ammonium perchlorate (AP) using Co3O4 as catalyst was studied by TG-DSC. The results indicated that the morphology of prepared Co3O4 particles was cubic octahedral and it has better catalytic property. After 10% Co3O4 was added, the decomposition temperature of AP reduced about 51℃, the decomposition rate was very fast and its exothermic region was centralized, with the amount of heat release increasing 287J/g.2. Co3O4 powder prepared by hydrothermal method was gone through situ polymerization and then the composite materials Co3O4/PANI was obtained. The feasibility of degradation of activated dye B-GFF using Co3O4/PANI was studied and the influence of some factors such as light, concentration of dye and usage of catalyst on photocatalytic degradation rate was dicussed. The analysis showed that polyaniline which coated the surface of Co3O4 nanoparticles could not effect crystal properties of Co3O4 nanoparticles; The adulteration of Co3O4 nanoparticles maybe improve the thermal stability of PANI. When illumination time was 2h, Co3O4/PANI haa very good degradation effect, with the degradation rate of activated dyB-GFF up to 95%. This is attributed to adsorption of PANI in the earlstages of degradation and photochemical degradation in the late periodwhich illustrated that Co3O4 and PANI had a good synergistic effect.3.Using CoCl2·6H2O, NiCl2·6H2O and ammonia water as cobalt sourcenickel source and precipitating agent, respectively, the intermediate producNi(OH)2-Co(OH)2 was obtained by the method of simple liquicoprecipitation and calcined it, then the Co3O4-NiO composite particlewere gotten. Co3O4-NiO was modified by ethylenediamine. Before and aftemodification, the changes of structure and morphology of Co3O4-NiO weranalyzed. Meanwhile, by virture of electrochemical workstationelectrochemical supercapacitors properties of Co3O4-NiO electrode materiasuch as cyclic voltammetry, galvanostatic charge-discharge and ACimpedance were tested. The consequence manifested that the porosity angood dispersity of Co3O4-NiO composite particles after modificatioavailed to the increase of surface area. Compared with the unmodifiedCo3O4-NiO obtained at caclined temperature 300℃showed excellenelectrochemical performance after modification and its single electrodspecific capacitance was up to 1202F/g at the potential window of 0-0.4Vwhich increased 171F/g. |
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