Zhang Wei, Wang Qiao, Qin Fan, Zhou Huamin, Lu Zhong, Chen Rong
Key Laboratory for Green Chemical Process of Ministry of Education and School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, 430073, P. R. China.
J Nanosci Nanotechnol. 2011 Sep;11(9):7794-801. doi: 10.1166/jnn.2011.4722.
Palladium nanoparticles (NPs) were successfully synthesized via a rapid and facile microwave route in HEPES (2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid) buffer solution. The shape- and size-controlled Pd nanoparticles could be obtained by one-step method without dependence of seed-mediated growth. The capping agent plays a key role in the formation of Pd NPs with different shape and size, which could be tuned by varying capping agents such as polyvinylpyrrolidone (PVP), cetyltrimethylammonium bromide (CTAB), sodium citrate (Na3(cit)) and potassium bromide (KBr). The size-dependent catalytic activities of the obtained Pd NPs for Suzuki coupling reaction were also investigated. It demonstrated that the catalytic activity of Pd NPs was enhanced regularly with the decrease of particle size. Pd NPs less than 10 nm exhibited better catalytic activities for Suzuki reaction than the commercial Pd/C catalyst. Pd/MWCNTs and Pd/SBA-15 nanocomposites were also prepared by a facile method and afforded good catalytic activity and reusability. This "green" synthetic protocol could be used as a general method for the rapid synthesis of transition metal nanoparticles.
通过在HEPES（2-[4-(2-羟乙基)-1-哌嗪基]乙磺酸）缓冲溶液中采用快速简便的微波路线成功合成了钯纳米颗粒（NPs）。无需种子介导生长，通过一步法即可获得形状和尺寸可控的钯纳米颗粒。封端剂在不同形状和尺寸的钯纳米颗粒形成过程中起关键作用，通过改变封端剂（如聚乙烯吡咯烷酮（PVP）、十六烷基三甲基溴化铵（CTAB）、柠檬酸钠（Na3(cit)）和溴化钾（KBr））可对其进行调控。还研究了所得钯纳米颗粒对铃木偶联反应的尺寸依赖性催化活性。结果表明，钯纳米颗粒的催化活性随粒径减小而有规律地增强。小于10 nm的钯纳米颗粒对铃木反应的催化活性优于商业钯/碳催化剂。还通过简便方法制备了钯/多壁碳纳米管和钯/SBA-15纳米复合材料，它们具有良好的催化活性和可重复使用性。这种“绿色”合成方案可作为快速合成过渡金属纳米颗粒的通用方法。
