Preparation of PW@CaCO3 phase change microcapsules modified by ZnO nanoparticles with excellent photocatalytic and thermal properties

We utilized an in-situ polymerization method to dope zinc oxide (ZnO) nanoparticles onto the surface of the inorganic calcium carbonate (CaCO3) shell capable of encapsulating paraffin wax (PW) cores, and synthesized a novel bifunctional microcapsule, which can be applied to optical catalysis and thermal energy storage. The PW@CaCO3/ZnO microcapsules with the varying ZnO nanoparticles were successfully synthesized. The micromorphology, chemical components, thermal properties, and photocatalytic applications of microcapsules doped with various ZnO concentrations were investigated. The results indicated that the PW@CaCO3/0.03%ZnO (i.e., the mass ratio of ZnO to PW of 0.03 wt%) exhibited the greatest thermal storage effectiveness and capacity with regard to all the samples. Under exposure to a particular wavelength of ultraviolet light, the PW@CaCO3/ZnO microcapsules can degrade the methylene blue dye solution by photocatalysis. The photocatalytic effect of the dye solution with PW@CaCO3/1.50%ZnO was the best after 12 h of exposure to ultraviolet radiation, and the degradation rate reached 98.97 %. In the spheres of energy conservation and environmental preservation, the PW@CaCO3/ZnO microcapsules offer a wide range of potential applications.