Pd/ZnO和Ag/ZnO复合纳米粒子的制备、表征及光催化活性

 用焙烧前驱物碱式碳酸锌的方法制备了ZnO纳米粒子，采用光还原沉积贵金属的方法制备了Pd／ZnO和Ag／ZnO复合纳米粒子，并利用ICP，XRD，TEM和XPS等测试技术对样品进行了表征，初步探讨了贵金属在ZnO纳米粒子表面形成原子簇的原因．以光催化氧化气相正庚烷为模型反应，考察了样品的光催化活性以及贵金属沉积量对催化剂活性的影响．结果表明：沉积适量的贵金属，ZnO纳米粒子光催化剂的活性大幅度提高．同时，深入探讨了表面沉积贵金属的ZnO纳米粒子光催化剂活性有所提高的内在原因．

Preparation and Characterization of Pd/ZnO and Ag/ZnO Composite Nanoparticles and Their Photocatalytic Activity

ZnO nanoparticles were prepared by calcining the precursor, zinc carbonate hydroxide, and Pd/ZnO and Ag/ZnO composite nanoparticles were obtained by photoreduction method for depositing noble metal. The samples were characterized by ICP, XRD, TEM and XPS techniques. The possible reasons of forming atomic clusters of noble metal on the surface of ZnO nanoparticles were discussed. Moreover, the photocatalytic activity of the samples was examined by using photocatalytic oxidation of gas phase n-heptane as a model reaction, and the effects of the noble metal content on the photocatalytic activity were investigated. The results indicated that the photocatalytic activity of ZnO nanoparticles can be greatly improved by depositing appropriate amount of noble metal on their surface. The essential reasons why Pd/ZnO and Ag/ZnO composite nanoparticles exhibited higher photocatalytic activity than ZnO nanoparticles were further probed into. The results indicated that the increase in surface contents of oxygen vacancies, hydroxyl groups and adsorbed oxygen as well as the increase in separation efficiency of photoinduced electron-hole pairs are responsible for the increase in activity after depositing noble metal on ZnO nanoparticle surface.