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通过一种小体积、连续性还原反应方法,制备出高浓度、大体积胶体Pd活化液,并采用SEM、TEM、XRD和XPS等手段表征其形貌、结构及元素组成特征,采用化学镀Cu及其电化学测试研究胶体的催化性能。结果表明:该方法能够制备出平均粒径低于4 nm且分布均匀的Pd胶核颗粒;在Pd含量低于25 mg/L时,活化液仍具有化学镀催化性能。研究发现:Pd胶团的外壳结构对活化能力起着重要作用,胶团外壳由Sn~(2+)、Sn~(4+)及Cl~-等组成,可形成2种络合体结构,即[PdSn2]Cl_6和[PdSn3]Cl_8,由于[PdSn3]Cl_8在解胶中不能水解,可导致胶团丧失活性。该制备方法可减少[PdSn3]Cl_8胶团结构的发生,提高了Pd胶体的活化性能。
The high concentration and large volume colloidal Pd activating solution was prepared by a small volume continuous reduction method. The morphology, structure and elemental composition were characterized by SEM, TEM, XRD and XPS. And its electrochemical testing of colloidal catalytic properties. The results show that this method can prepare Pd colloidal particles with an average particle diameter less than 4 nm and uniform distribution. When Pd content is less than 25 mg / L, the activating solution still possesses electroless catalytic activity. It is found that the shell structure of Pd micelles plays an important role in the activation ability. The micellar shell consists of Sn 2 +, Sn 4+ and Cl ~ Namely [PdSn2] Cl_6 and [PdSn3] Cl_8, because [PdSn3] Cl_8 can not be hydrolyzed in gum cleavage, which leads to the loss of activity of micelles. The preparation method can reduce the occurrence of [PdSn3] Cl_8 micelle structure and improve the activation performance of the Pd colloid.