方波电势脉冲法制备金、铂和钯枝晶与多孔金

发布时间：2018-12-26 12:16

【摘要】：金、铂和钯等纳米材料由于其特殊的结构以及由此产生的一系列纳米效应,广泛应用于化工、能源、电子等领域。因此,它们的制备备受关注。如今,人们已能利用很多方法来制备不同形态的贵金属纳米材料。其中,电化学方法由于其反应可控性好、条件温和、污染少、适用范围广等优点,是一种前途广阔的纳米材料制备方法。本文发展了方波脉冲技术制备金、铂和钯枝晶以及多孔金的方法。主要工作如下： 1.金电极在2 M HCl中歧化(0.9 V, vs. Hg|Hg2SO4, K2SO4) 50 s后,转移至酸性(H2SO4, HClO4)、碱性(NaOH)或中性(Na2SO4)溶液中,通过方波电势脉冲,可快速制备均匀致密的枝晶金膜。枝晶的形成过程涉及金的氧化-还原循环,金原子的表面扩散,金纳米粒子的融合和扩散控制下的聚集与生长。并探究了电势上下限、波形、频率、电解液和电极表面状态等对枝晶生长的影响。该枝晶金膜具有高电催化活性和强表面增强拉曼散射效应,在修饰硫醇后具有超疏水性。 2.光亮铂电极在含H2PtCl6的H2SO4溶液中,通过方波电势脉冲,可制备较均匀致密的枝晶铂。枝晶的形成过程涉及铂的氧化-还原循环,铂原子的表面扩散和重排,铂纳米粒子的融合和扩散控制下的聚集与生长。并探究了频率、电势上下限、硫酸浓度等因素对枝晶生长的影响。该枝晶铂膜具有高电催化活性和强表面增强拉曼散射效应,在修饰硫醇后具有超疏水性。 3.光亮钯电极在含PdCl2的H2S04溶液中,通过方波电势脉冲可制备出枝晶钯；并考察了浓度对枝晶结构的影响,以及枝晶钯对乙醇的电催化效果。 4.光亮金电极在2M HCl溶液中电势阶跃至0.9 V处理50 s后,转移到2M NaOH溶液中方波电势脉冲处理100-500 s,可快速制备出均匀的三维微米／纳米多孔结构。所制备的三维微／纳多孔金具有较大的表面积,具有多种功能：对葡萄糖的电催化氧化表现出较高的活性,可作为表面增强拉曼散射的基底,在修饰单层硫醇后具有超疏水性。
[Abstract]:Gold, platinum and palladium nanomaterials are widely used in chemical, energy, electronic and other fields because of their special structure and a series of nanometer effects. Therefore, their preparation has attracted much attention. Nowadays, many methods have been used to prepare noble metal nanomaterials in different forms. Electrochemical method is a promising preparation method for nanomaterials due to its advantages such as good controllability mild conditions less pollution and wide application range. The preparation of gold, platinum and palladium dendrite and porous gold by square wave pulse technique has been developed in this paper. The main work is as follows: 1. The gold electrode transferred to acid (H _ 2SO _ 4, HClO4) and alkaline (NaOH) or neutral (Na2SO4) solution for 50 s after being disproportionated (0.9 V, vs. Hg Hg2SO4, K2SO4) in 2 M HCl. The uniform and dense dendritic gold film could be rapidly prepared by square wave potential pulse. The dendrite formation process involves the redox cycle of gold, the surface diffusion of gold atoms, the fusion of gold nanoparticles and the aggregation and growth of gold nanoparticles under the control of diffusion. The effects of potential upper and lower limits, waveform, frequency, electrolyte and electrode surface state on dendritic growth were investigated. The dendritic gold film has high electrocatalytic activity and strong surface-enhanced Raman scattering effect, and has super hydrophobicity after modification of mercaptan. 2. Dendritic platinum with uniform density can be prepared by square wave potential pulse in H2SO4 solution containing H2PtCl6. The dendrite formation process involves the oxidation reduction cycle of platinum, the surface diffusion and rearrangement of platinum atoms, the aggregation and growth of platinum nanoparticles under the control of diffusion. The effects of frequency, potential upper and lower limits and sulfuric acid concentration on dendritic growth were investigated. The dendrite platinum film has high electrocatalytic activity and strong surface-enhanced Raman scattering effect, and has super hydrophobicity after modification of mercaptan. 3. Dendritic palladium can be prepared by square wave potential pulse at bright palladium electrode in H2S04 solution containing PdCl2, and the effect of concentration on dendritic structure and electrocatalytic effect of dendritic palladium on ethanol are investigated. 4. The bright gold electrode has a potential order of 0.9 V in 2m HCl solution for 50 s, then transferred to a square wave potential pulse in 2 M NaOH solution for 100-500 s. The uniform three-dimensional micron / nano-porous structure can be rapidly prepared. The three dimensional micro / nano porous gold has a large surface area and has many functions: the electrocatalytic oxidation of glucose exhibits high activity and can be used as a surface-enhanced Raman scattering substrate with superhydrophobicity after modification of monolayer mercaptan.
【学位授予单位】：浙江师范大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TB383.1

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