钯纳米粒子/嵌段共聚物复合胶束的制备及催化性能

嵌段共聚物聚苯乙烯-b-聚4-乙烯吡啶(PS-b-P4VP)在酸水(pH=2)中自组装形成PS为核,P4VP为壳的核-壳胶束(约为30 nm)。在核-壳胶束酸水溶液(pH=2)中加入氯化钯,钯离子与P4VP络合形成聚苯乙烯为核、聚4-乙烯吡啶/钯离子为壳的胶束。进一步加入硼氢化钠(NaBH4)原位还原钯离子,得到钯纳米粒子(粒径约为3 nm)位于P4VP壳层的复合胶束。复合胶束对4-硝基苯酚还原为4-氨基苯酚的反应中表现出催化活性,动力学研究结果表明,反应为一级反应,反应速率随复合胶束浓度的增加及反应温度的升高而加快。

Preparation and Catalytic Property of Complex Micelles Containing Palladium Nanoparticles and Block Copolymers

Block copolymers,polystyrene block poly(4-vinyl pyridine)(PS-b-P4VP),self-assembled into core-shell micelles with PS as the core and P4VP as the shell in acidic water(pH=2).The PdCl2 was added to the core-shell micelles solution and the ionic Pd2+ then complexes with P4VP chains to form micelles with PS as the core and P4VP/Pd2+ as the shell.The complex micelles containing Palladium nanoparticles in the P4VP surfaces of the micelles were obtained by in-situ reducing the Pd2+ of the micelles in acidic water(pH=2) using NaBH4 as the reductant.The complex micelles can be applied to catalyze the reduction of 4-nitrophenol into 4-aminothenol and the reaction shows one-order kinetics,furthermore,the reactive rate increases with increasing concentration of micelles and reactive temperature.