NH_4F改性MWCNTs负载Pd纳米粒子的电催化性能研究

Electrocatalytic performance of palladium nanoparticles supported on functionalized MWCNTs by ammonium fluoride for methanol electro-oxidation

以无机物NH4F为改性剂,对NaOH处理后的多壁碳纳米管(f1-MWCNTs)进行共价键表面修饰得到f2-MWCNTs,将前驱体溶液在紫外光照射下边还原边负载于f2-MWCNTs表面,制得Pd/f2-MWCNTs催化剂。利用FT-IR、TEM、EDS、XRD和XPS等手段对其进行表征,结果表明f2-MWCNTs表面形成C—F、C—N等化学键和Pd/f2-MWCNTs表面存在Pd-F配位键,通过这些化学键的相互作用改变了Pd的电子结构,从而提高Pd纳米粒子的负载率和分散性。通过电化学测试发现,Pd/f2-MWCNTs催化剂对甲醇具有优异的催化性能,其质量电流密度是JM公司商业Pd/C催化剂的2.87倍。

In this paper, multi-walled carbon nanotubes （MWCNTs） were firstly pretreated with sodium hydroxide solution （fl-MWCNTs）, and then f1-MWCNTs were covalently modified by ammonium fluoride （f2- MWCNTs）, which were used as a new support for Pd nanoparticles. The new catalysts （Pd/f2-MWCNTs） were prepared by one-step photochemical reduction technique. FT-IR, TEM, XRD and XPS measurements revealed that the C-F and C-N covalence bonds were easily formed on the surface of f2-MWCNTs.In addition, the surface of Pd/f2-MWCNTs had the coordinate bonds Pd-F. The mutual interaction of these chemical bonds made the change of electronic structure of Pd,which enhanced the loading effect and dispersity of Pd nanoparticles. Cyclic electrochemical experiments indicated that electro-catalytic activity of Pd/f2-MWCNTs catalyst for methanol in alkaline medium was about 2.4 times higher than that of the commercial Pd/C （JM） catalyst at the same conditions.