运用CO分子探针红外光谱研究不同尺度和分散状态的钯纳米粒子的红外光学性能.结果表明,粒子尺度为6.6nm分散的球型钯纳米粒子(Pdn)和粒子尺度为100～150nm分散的立方体型钯纳米粒子(Pdncube)均给出两个不同吸附方式的桥式CO红外谱峰,其吸收峰位置约在1970cm-1和1910cm-1.将Pdn引入到电极表面后,通过界面电化学诱导使之形成团聚体(Pdnag),其红外光学性能发生显著变化,表现为随着界面电化学诱导时间的增加,其1970cm-1处的谱峰方向从正常转为异常.本研究进一步证明红外谱峰方向的倒反是由于粒子间的相互作用引起的.

Pd nanoparticles with different sizes and dispersed states were prepared. Their infrared optical properties were studied with CO molecule probe. The infrared spectroscopic investigation revealed that Pd_(n)of 6.6 nm and Pd_n~(cube)of 100～150nmexhibit normal IR absorption. The center of IR bands are around 1 970 cm~(-1 )and 1 910cm~(-1). Pd_(n)is introduced into the surface of electrode, and is induced by interface electric fieldto form the aggregation of nanoparticles Pd_n~(ag). The Pd_n~(ag)has a different IR optical property from Pd_(n). The direction of IR absorption band of Pd_n~(ag)is changed from normal to abnormal at 1 970cm~(-1)with the increase of polarization time. The present study demonstrated progressively the reversion of direction of IR band is general phenomena produced by the aggregation nanoparticles that there is interparticle interaction.