金纳米棒@碳中空胶囊的制备及催化性能

Preparation of Gold Nanorods@C Hollow Capsules and Applications in Catalysis

以聚吡咯为碳壳前驱体制备了金纳米棒镶嵌于碳壳内的中空胶囊.先合成羧基修饰的聚苯乙烯微球和十六烷基三甲基溴化铵稳定的金纳米棒;再利用二者之间的静电力将金纳米棒组装在聚苯乙烯微球表面;最后,通过氧化聚合将聚吡咯壳包覆在聚苯乙烯@金纳米棒复合物的表面.在氮气保护下经高温煅烧,聚吡咯壳被碳化为碳壳的同时聚苯乙烯微球分解,从而制得金纳米棒@碳中空胶囊.在煅烧过程中,由于碳壳的保护,金纳米棒很好地保持了"棒状"形貌.通过调节吡咯单体的浓度,可以控制聚吡咯壳和碳壳的厚度.金纳米棒@碳中空胶囊在以NaBH4为还原剂还原亚甲基蓝的反应中表现出良好的催化活性.

Hollow capsules with gold nanorods （GNRs） embedding in the carbon shell were prepared by poly pyrrole（PPy） as carbon precursor. The carboxylic-capped polystyrene （PS） nanoparticles were firstly synthe sized, then the hexadecyl trimethyl ammonium bromide-stabilized GNRs were self-assembled onto their surface through the electrostatic interaction, and formed PS@ GNRs composites. Next, PPy was coated on the surface of PS@ GNRs composites; meanwhile, GNRs were embedded in the PPy shell. After calcination in nitrogen atmosphere, the PPy shell was carbonized to the carbon shell and the PS nanoparticles decomposed at the same time. During heat-treatment process, GNRs preserved rod-like morphology without aggregations due to the pro- tection of carbon shell. Upon varying the concentration of pyrrole monomer, both PPy and carbon shell thick- nesses could be readily turned. The GNRs@ C hollow capsules showed excellent catalytic performance in the reduction of methylene blue with sodium borohydride as reducing agent.