| Based on the excellent physical and chemical properties, thermal stability, the researchers pay close attention to the research of transition metal oxides (cobalt, manganese). Co3O4has been widely used in many fields, such as catalysis, lithium ion battery, pressure sensitive ceramics, inorganic pigments, super capacitors and other fields. MnO2is widely used in catalysis, batteries, and super capacitor and other fields. The traditional synthetic method of transition metal oxides is mainly by high temperature calcination, but this method exists many drawbacks, such as larger particle size, wide distribution of particle size and low purity, these shortcomings limit the application in various fields.The paper prepared a series of cobalt oxide and manganese dioxide catalyst samples which synthesized by hydrothermal synthesis method and the traditional high-temperature-calcination method. In this paper, the synthesis conditions have been investigated, such as crystallization time, reaction temperature and PH, and the influence of reaction conditions on catalyst morphology was clearified. In addition, a series of characterization methods for the prepared catalysts has been used, such as XRD, H2-TPR, BET, XPS, SEM, oxygen isotope exchange, etc. For the five kinds of the cobalt oxide samples, catalytic combustions for CH4and CO were inverstigated respectively. Carbon monoxide oxidation was investigated over manganese dioxide with diverse morphologies.Through different characterization methods, we can comfirm that the large specific surface area and good ability of redox correspond to excellent catalytic activity. The cobalt oxide and manganese dioxide samples can get similar rules. By oxygen isotope exchange technique on the surface oxide of the as-prepared samples and internal dynamics parameters of oxygen transfer rate was tested. The migration ability of oxygen species and the corresponding relation of catalytic activity were studied. |
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