Synthesis, Characterization And Catalytic Properties Research Of Cobalt Based Catalysts

The catalytic activity and selectivity of the cobalt based metal nanometer materials are closely related to the crystal structure, morphology and surface valence, composition elements and particle size. Different morphology has different active sites exposed, thus affect the catalytic activity; The surface valence of metal catalyst affect the adsorption between catalyst and reactants, which affect the catalytic activity. For bimetallic catalyst, also due to the synergy of two metals, makes it may has the better physical and chemical performance characteristics than the one kind of metal. The size of the particle affects the specific surface area and the amount of load, which affect the catalytic effect. So this article from the macroscopic perspective, through regulate the synthesis method for synthesis of micro with specific structure and morphology of cobalt base nanometer materials.In the first part of this article, using solvent hot method reducing cobalt acetate, with oil amine as the reducing agent and surfactant, CO small molecular gas as the auxiliary reduction and modification, by magnetic stirring in the dynamic kettle, to prepare the products with the surface most are zero valent and not easy to be oxidized nanometer cobalt chain catalysts. Mainly studied the assisted reduction of small molecules CO gas pressure and stirring speed affect the formation of chain structure. With TEM, XRD, SEM, XPS, FT-IR, BET and magnetic properties test analysis methods to characterization the structure, morphology, valence distribution and the change of magnetic properties, we have also put forward the formation mechanism of the nanometer chain structure. Put the chain cobalt and granular cobalt into Fischer-Tropsch synthesis which under the condition of pretreatment or without pretreatment in hydrogen, In the constant temperature of 250℃, constant reaction pressure of 0.4Mpa, With TCD and FID detector CO conversion, CH4, and C2-C4 products selectivity and yield, at last calculate the TOF.In this paper, the second part is based on the synergy of bimetal may be better than that of single metal features, in the mechanical stirring dynamic kettle with two-step Ni@Co bimetallic core-shell structure was synthesized. We have also discussed the mole ratio of two metals, the second step of the reaction time, different reaction devices, washing the reaction product of the first step, one-step method, etc which influence of product structure. With TEM, XRD, SEM, line scanning plane scanning and magnetic properties test analysis methods to characterize the structure, morphology and magnetic properties change of the double metal materials, we have also put forward the formation mechanism of the core-shell structure.In this paper, the third part based on nanoparticles size effect, small size of nanoparticles with larger specific surface area and more easy to load on the metal oxides such as Al2O3, SiO2 and so on, which affect the catalytic effect. Reduction of cobalt acetate use solvent hot method, with oil amine as the reducing agent and surfactant, the reaction was processed in the oil bath pot to obtain small size particles around 20 nm, we have also discussed the factors such as reaction time, reaction temperature on the influence of the synthesis. Load the small size particles, which synthetic with or without CO, to the nanometer SiO2 or Al2O3.