| Summary: | 碩士 === 國立高雄應用科技大學 === 化學工程與材料工程系 === 97 === Ag/ZnO nanomaterials were synthesized by three different processes in this study. The Ag-deposited ZnO obtaining from process A were prepared by mixing Zn(NO3)2•6H2O and hexamethylenetetramine (HMT) at a mole ratio of 2:1 as well as AgNO3. The process B first prepared ZnO by reacting with Zn(NO3)2•6H2O and HMT at a mole ratio of 2:1; then, The Ag-deposited ZnO rods were formed by adding AgNO3 to the ZnO suspension. The Ag/ZnO heterostructures obtaining from process C were first prepared ZnO nanoparticles by heating Zn(CH3COO)2•2H2O at 65C and pH 13 in the presence of methanol, followed by reacting with AgNO3. The Ag-deposited ZnO preparing by process A were the ZnO rods with a diameter around 100 nm (aspect ratio of 5:1) loaded with the Ag nanopartitcles with a diameter around 50 nm. The diameter of the Ag-deposited ZnO rods forming in process B were about 200 nm, which were loaded with the Ag nanoparticles (20-30 nm in diameter). The Ag/ZnO heterostructures from process C were the Ag nanoparticels (20-30 nm in diameter) dispersing in the ZnO nanoparticles (30 nm in diameter). The XRD and TEM analysis showed that silver oxide was not observed. There was no bonding between ZnO and Ag; namely, Ag nanoparticles were deposited on the surfaces of ZnO rods or nanoparticles. Photocatalysis experiments (irradiated by 365 nm) showed that the photocatalytic activity of the Ag/ZnO prepared from process C was better than the products from process A and B. It can be expected that the specific surface area is one of the critical factors affecting the photocatalytic activity. In addition, the photocatalytic activity of Ag/ZnO was significant higher than ZnO, indicating that the photogenerated elections could be captured by Ag, which decreased the recombinantion of electron-hole pairs and improved the photocatalytic acitivty. Additionally, the UV/visible spectrophotometer observation demonstrated that the ZnO nanoparticles preparing by process C were transparent in visible light and were capable of absorbing UV. It can be seen that the ZnO nanoparticles from process C is a promising agent for sunscreen.
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