金属纳米材料表面配体聚集效应

Assembling Effects of Surface Ligands on Metal Nanomaterials

金属纳米材料表面配体不仅可以稳定金属纳米颗粒,辅助合成特定尺寸和形貌的纳米材料,还可用于调控金属纳米颗粒的表面化学性质。由于现有表征技术的局限性,金属纳米材料表面有机配体的结构和功能一直以来并未被深入研究。得益于分子结构明确金属纳米团簇和其他模型纳米材料体系的发展,配体在金属纳米材料表面的精确配位结构及其对催化过程的促进作用正不断被揭示出来。金属表面有机分子配位不仅可以调控表面金属电子结构,还可以分割表面原子周期性结构。表面有机配体的聚集可以进一步在金属表面构筑3D空间结构,改变纳米材料亲疏水性,并影响催化底物和反应中间体与表面的相互作用强弱和吸附构型。此外,有机配体与表面金属所组成的界面还可以构筑新的活性位点,改变催化反应路径,从而提升催化反应活性和选择性。金属纳米材料表面有机配体的聚集效应使得异相纳米材料可以同时表现出均相催化和酶催化的优势。

Surface ligands on metal nanomaterials play a crucial role in the controlled synthesis of metal nanoparticles with specific size and morphology.However,the detailed molecular-level structures of surface ligands are difficult to be determined by conventional characterizations,leading to our poor understanding over the effects of surface ligands on the chemical properties of metal nanomaterials.Benefiting from the development of metal nanoclusters and other model nanomaterials,increasing research effort has been devoted to revealing the detailed coordination structure of surface ligands on metal nanomaterials and their catalytic effects.The coordination of organic molecules on the metal surface can not only regulate the electronic structure of the surface metal,but also alter the periodic structure of the surface atoms.Moreover,the assembling of surface organic ligands can create 3D spatial structure on the metal surface for manipulating the interaction strength and configuration of reactants and intermediates with the catalytic surface.The interface created by having organic ligands modify metal surface can also lead to the formation of new catalytic sites for changing the catalytic reaction pathways to improve the catalytic activity and selectivity.The assembling effects of surface ligands on metal nanomaterials make them exhibit advantages of heterogeneous catalysis and homogeneous catalysis.