中文摘要：

利用同步辐射X射线吸收精细结构谱学（XAFS）等技术研究了不同种类表面活性剂对反应生成的金纳米颗粒的原子和电子结构的影响.XAFS和电镜结果表明三苯基膦、十二胺和十二硫醇3种表面活性剂与金纳米颗粒的相互作用依次增强,三苯基膦分子中的P原子与金纳米颗粒表面的Au原子产生弱的物理吸附,生成的金纳米颗粒的尺寸为7.2 nm;而十二胺和十二硫醇则分别以头基N原子和头基S原子与金纳米颗粒表面的Au原子形成强的Au-N和Au-S共价键,有效地阻止金纳米颗粒的长大和聚集,其颗粒尺寸为3.1nm.同时,金纳米颗粒中第一近邻Au-Au键长由三苯基膦的2.82 A减小到十二硫醇的2.79A,相应的配位数则由11.3减少为10.1,这是由于十二硫醇与纳米颗粒具有强的相互作用导致.XAFS的近边谱表明在十二硫醇覆盖的情况下可以观察到明显的表面Au原子的电子转移现象.

英文摘要：

X-ray absorption fine structure （XAFS） was used to study the atomic and electronic structure of Au nanoparticles affected by three kinds of surfactants, triphenylphosphine （PPh3）, dodecanamine （C12H27N） and dodecanethiol （C12 H26 S）. XAFS and TEM results indicate that the surface interaction intensity between Au nanoparticles and surfactants is in the order of C12 H26 S, C12 H27 N and PPh3. The head-group P atom in the PPh3 molecule is weakly bonded Au adatoms of Au nanoparticles, and the resulting nanoparticle size is about 7. 2 nm. However, the head-group N atom in C12 H27N and S atom in C12H26S are strongly bonded to Au adatoms, forming Au--N and Au--S covalent bonds, respectively, which effectively inhibits the aggregation of nanopartieles and leads to the smaller size of 3.1 nm. Furthermore, the bond length of the first nearest Au-Au coordination deereases from 2.82 A for PPh3 capping to 2.79 A for C12H26S capping, along with the decrease of Au--Au coordination number from 11.3 to 10. 1, indicating the strongest interaction between C12 H26S and Au nanoparticles. The XANES results indicate that the significant charge transfer of Au nanoparticles only occurs for the case of C12 H26 S capping.