The Research On The Preparation And Characterization Of Metal Oxides

In recent years, nature is seriously damaged, people have realized environmental pollution brings human survival crisis, environmental protection and management has become one of hot topics in the world. Because of the increasing global warming, people are looking for effective ways to fix the main component of greenhouse gas CO2. The oxygen vacancy formed by spinel ferrite (MFe2O4) reduced partially has a high CO2hydrogenation methanation activity and is useful to realize CO2conversion, not only can reduce greenhouse effect, but also can produce new energy resource CH4. Water pollution has also forced people to find better sewage treatment technology. Many investigations show that ZnO semiconductor material as photocatalyst has very high activity and can degrade organic pollutants.The first section of this thesis describes the nanocrystalline NiFe2O4was synthesized by soft template method, and was characterized via XRD, SEM, VSM, BET and ICP. Finally, we choose NiFe2O4with the well crystal structure, large surface area, and good magnetic properties and better dispersion, as catalysts for CO2methanation.We investigated the effect of the reaction temperature, pH value, reaction time on properties of NiFe2O4. The result shows that at the condition of40℃, pH of9and48h NiFe2O4was sythesized with fine crystalliniy and good dispersion, the saturation magnetization of the sample was51.39emu-·g-1and high specific surface area104.45m2·g-1. As-synthesized samples at different reaction temperature were used as catalysts for CO2hydrogenation methanation, the results show that as-synthesized sample at40℃had the highest CO2conversion ratio,38.64%.The second section describes ZnO was synthesized by solvothermal method and hydrothermal method. We investigated the photocatalytic activity of ZnO with the well crystal structure and regularer morphology by degradation of Rhodamine B under ultra-visible light. The results showed that the ZnO exibit good photocatalytic performance.ZnO microspheres were synthesized by solvothermal method with ethylene glycol as solvent, and acetates as additive, and invesitigated the effect of additives, reaction temperature and time on properties of ZnO. ZnO microspheres were characterized. The results showed that with KAc as additive, ZnO microspheres were sythesized with fine crystalliniy, uniform particle size at180℃for24h.ZnO were synthesized by hydrothermal method with sodium alginate (SA) and carboxymethyl cellulose sodium (CMC) as the structure directing agent. The effect of molar ratios of zinc salt and structure directing agent on morphology of ZnO was investigated and as-synthesized samples were characterized. The results show that under pH of9.0, at120℃for12h, with initial molar ratio of n(ZnCl2):n(SA) as100:12, ZnO had been synthesized with well crystalliniy and regularer secondary structure of pinecone shape; with the ratio of n(ZnCl2) n(CMC) as50:12, as-synthesized sample with well crystalliniy and regularer secondary structure of spherical shape.As-synthesized ZnO with the two structure directing agents had best photocatalyitc performance when their concentrations both were0.5g/L. The catalytic performance of as-synthesized sample with SA as additive was better than that with CMC as additive.