Study On Phase Transformation Characteristics And Catalytic Performance Of Photocatalytic Phase Change Microcapsules

In this paper,phase change microcapsules were prepared by sol-gel method and hydrothermal method using butyl titanate and fatty acid.The effects of emulsifier dosage and core shell ratio on the microstructure of phase change microcapsules were studied to determine the optimum process parameters.A new bifunctional microcapsule with heat storage performance and high catalytic activity was successfully synthesized by adding different amounts of graphene to modify the catalytic performance of TiO2.The microcapsules were used to prepare the interior wall insulation coating.The basic properties of the coating were tested.The samples were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),differential scanning calorimetry(DSC),thermal constant analyzer and ultraviolet spectrophotometer.The results show that the TiO2/PCM microcapsules are spherical and the particle size is between 30 and 50μm,when the amount of sodium dodecyl sulfate is 5%and the ratio of butyl titanate and fatty acid is 1:1,ruptured microcapsules showed a distinct core-shell structure.It can be seen from the X-ray diffractometer that the titanium dioxide shell is mainly anatase type,and the coating process does not cause the crystal form to change.The thermal conductivity of TiO2/PCM microcapsules was 0.497 W/(m·K),increased by 31.2%,the latent heat of change was 84.3 kJ/kg,and the coating rate was 74.5%.When the content of graphene is 3%,the thermal conductivity of TiO2-rGO/PCM microcapsules is 0.511 W/(m·K),increased by 34.8%and the latent heat of phase change is 83.1kJ/kg.When the dosage of TiO2/PCM is 1g/L and the concentration of Rhodamine b is 20mg/L,the degradation rate of Rhodamine b is about 71%under 2.5h light irradiation.When the content of graphene is 8%,the degradation rate of TiO2-rGO/PCM microcapsules can reach 88%after 2.5h.Therefore,the microcapsules prepared in this paper have good energy storage capacity and photocatalytic function,which will further expand the application field of phase change materials.