CeO_2@Au核壳结构纳米粒子的合成与性质研究

Synthesis and Properties of CeO_2@Au Core-Shell Structure Nanoparticles

采用沉淀法制备了球形CeO2纳米粒子,将其作为核粒子溶液,然后向其中滴加四氯合金酸溶液,在CeO2胶体表面利用柠檬酸钠还原[AuCl4]-离子,得到了CeO2@Au核壳结构纳米粒子。TEM分析表明,CeO2纳米粒子分散效果好,粒径为5 nm;CeO2@Au核壳粒子为球形,无团聚,平均粒径为15 nm。XRD分析表明,CeO2@Au核壳粒子为晶型结构,属于立方晶系,CeO2空间群为O5H-FM3M,Au的空间群为Fm-3m。UV-vis分析发现,CeO2@Au核壳粒子在300和520 nm处呈现出两个比较强的吸收峰,分别对应于CeO2胶体溶液的吸收峰和金粒子的表面等离子共振吸收峰。EDS分析了核壳结构CeO2@Au纳米粒子中存在Ce,O和Au 3种元素。XPS分析表明,Ce3d3/2和Au4f电子结合能与标准结合能相比发生了变化,说明CeO2与Au之间存在着相互作用。

Spherical CeO2 nanoparticles were prepared by precipitation method. The CeO2 @ Au core-shell nanoparticles were synthesized by chemical reduction of [ AuCl4 ]- on the surface of as-prepared CeO2 colloids using the sodium citrate as reducing agent. The TEM images showed that the CeO2 nanoparticles were well dispersed and the particle diameter was about 5 nm. The CeO2 @ Au core-shell nanoparticles had perfectly spherical shape with non-agglomeration and the a narrow size distribution, average particle size was about 15 nm. According to the XRD results, the CeO2 @Au core-shell was crystalline and cubic in structure with space group OH5-FM3M of CeO2, space group Fm-3m of Au. The UV-vis results demonstrated that the two strong absorption spectrum were observed corre- sponding to the surface plasma band of the respective metal oxide and metal （viz. 300 nm for CeO2 and 520 nm for Au in CeO2 @ Au core-shell nanoparticles ）. The EDS analysis confirmed the presence of Ce, O and Au elements in core-shell structured CeO2 @ Au nanoparticles. According to the difference of Ce3d3/2 and Au4f orbital electron binding energy in XPS between experimental binding energy and standard binding energy, it could be inferred that there existed an interaction between Au and CeO2.