采用方波电位,在10x10-3MOl·l-1k2PTCl6+3x10-4MOl·l-1PbAC2+0.5MOl·l-1HClO4溶液中,于本体PT电极上电沉积制备出枝晶状PT薄膜.随着沉积时间的增加,枝晶长度逐渐由400nM增加到900nM,且枝晶上的小晶粒(--10nM大小)变得密集.根据循环伏安(CV)曲线中氢吸脱附电量可得出PT薄膜具有中等粗糙度(Cr=9-36),且电极表面的粗糙度随着沉积时间增加而增大.观察到PT薄膜上吸附态CO的原位红外光谱具有明显的增强吸收效应,当沉积时间为6MIn时所制得的枝晶PT电极的红外增强效应最大.CO呈现多种谱峰形状,随着沉积时间的增加,谱峰形状依次为左高右低的双极峰(类fAnO红外效应),单极向下(表面增强红外吸收),左高右低的双极峰,单极向上(异常红外效应),左低右高的双极峰和单极向下.这表明纳米材料薄膜所呈现出的特殊红外性能,与纳米材料的尺度和聚集状态等密切相关.所制备的枝晶状PT薄膜有望为深入认识纳米材料的特殊红外性能提供一个良好的模型材料.Dendritic Pt thin films are electrodeposited on bulk Pt electrodes in 10×10 -3 mol · L -1 K 2 PtCl 6 +3× 10 -4 mol · L -1 PbAc 2 + 0.5 mol · L -1 HClO 4 using square-wave potential pulses.As the deposition time increases, the length of the Pt dendrites increases from 400 to 900 nm, and the distribution density of Pt nanoparticles (--10 nm), which consist of coiled Pt dendrites, increases greatly.From hydrogen adsorption/ desorption obtained from cyclic voltammograms (CV), the surface of the dendritic Pt thin film electrodes has a relative roughness (C r ), which increases from 9 to 36 as the deposition time increases.Maximum enhanced IR absorption of adsorbed CO (CO ad ) is observed at the deposition time of 6 min.Anomalous infrared effects for CO ad are also seen on the dendritic Pt thin film electrodes.The line shapes of CO ad change with increasing deposition time, in order: bipolar→downward→bipolar→upward→bipolar→ downward bands.Fano-like infrared effects (bipolar), surface enhanced IR absorption (enhanced downward band), and abnormal IR effects (enhanced upward band) are highly dependent on the surface architecture of the nanostructures.The as-prepared dendritic Pt thin films provide model substrates for in-depth studies of the anomalous infrared effects of CO ad in metal nanostructures.国家自然科学基金(21073152;20933004;20833005;21021002);福建省高校杰出青年科研人才培育计划(JA10003)资助项目---
