微波辅助合成Ir-Pd双金属三八面体纳米晶及其电催化性能

Microwave-assisted synthesis of Ir-Pd bimetallic trioctahedral nanocrystals and their electrocatalytic properties

以Ir(acac)_3和H_2PdCl_4为前驱体,三缩四乙二醇(TEG)为溶剂和还原剂,抗坏血酸(AA)为共还原剂,聚乙烯吡咯烷酮(PVP)为稳定剂,KI为形貌控制剂,微波辐照120 s,得到形貌单一、大小均匀的Ir-Pd双金属三八面体纳米晶。反应体系中Ir(acac)_3∶H_2PdCl_4∶AA∶KI∶PVP最适宜摩尔比为1∶3∶2∶10∶15。利用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、X-射线粉末衍射(XRD)、X-射线光电子能谱(XPS)对其结构进行了表征。所合成的Ir-Pd双金属三八面体纳米晶催化甲酸电氧化的活性约为商业Pd黑的2.5倍。

Uniform and well-defined Ir-Pd bimetallic trioctahedral nanocrystals with an average size of 50 nm are synthesized by using Ir（ acac）3 and H2 PdCl4 as precursors,tetraethylene glycol（ TEG） as solvent and reduction agent,ascorbic acid（ AA） as a co-reduction agent,polyvinylpyrrolidone（ PVP） as a stabilizer,KI as a shape-controlled agent under microwave irradiation for 120 s.In the reaction system,the optimum molar ratio of Ir（ acac）3∶ H2 PdCl4∶ AA ∶ KI ∶PVP is 1 ∶3 ∶ 2 ∶ 10 ∶ 15. The products are characterized by transmission electron microscopy（ TEM）,scanning electron microscope（ SEM）,X-ray diffraction（ XRD） and X-ray photoelectron spectrometry（ XPS）. The electrocatalytic activity of the as-prepared Ir-Pd bimetallic trioctahedral nanocrystals for electro-oxidation of formic acid is around 2. 5 times that of the commercial Pd black.