發(fā)布時間：2018-12-26 12:16

【摘要】：金、鉑和鈀等納米材料由于其特殊的結(jié)構(gòu)以及由此產(chǎn)生的一系列納米效應,廣泛應用于化工、能源、電子等領域。因此,它們的制備備受關注。如今,人們已能利用很多方法來制備不同形態(tài)的貴金屬納米材料。其中,電化學方法由于其反應可控性好、條件溫和、污染少、適用范圍廣等優(yōu)點,是一種前途廣闊的納米材料制備方法。本文發(fā)展了方波脈沖技術(shù)制備金、鉑和鈀枝晶以及多孔金的方法。主要工作如下： 1.金電極在2 M HCl中歧化(0.9 V, vs. Hg|Hg2SO4, K2SO4) 50 s后,轉(zhuǎn)移至酸性(H2SO4, HClO4)、堿性(NaOH)或中性(Na2SO4)溶液中,通過方波電勢脈沖,可快速制備均勻致密的枝晶金膜。枝晶的形成過程涉及金的氧化-還原循環(huán),金原子的表面擴散,金納米粒子的融合和擴散控制下的聚集與生長。并探究了電勢上下限、波形、頻率、電解液和電極表面狀態(tài)等對枝晶生長的影響。該枝晶金膜具有高電催化活性和強表面增強拉曼散射效應,在修飾硫醇后具有超疏水性。 2.光亮鉑電極在含H2PtCl6的H2SO4溶液中,通過方波電勢脈沖,可制備較均勻致密的枝晶鉑。枝晶的形成過程涉及鉑的氧化-還原循環(huán),鉑原子的表面擴散和重排,鉑納米粒子的融合和擴散控制下的聚集與生長。并探究了頻率、電勢上下限、硫酸濃度等因素對枝晶生長的影響。該枝晶鉑膜具有高電催化活性和強表面增強拉曼散射效應,在修飾硫醇后具有超疏水性。 3.光亮鈀電極在含PdCl2的H2S04溶液中,通過方波電勢脈沖可制備出枝晶鈀；并考察了濃度對枝晶結(jié)構(gòu)的影響,以及枝晶鈀對乙醇的電催化效果。 4.光亮金電極在2M HCl溶液中電勢階躍至0.9 V處理50 s后,轉(zhuǎn)移到2M NaOH溶液中方波電勢脈沖處理100-500 s,可快速制備出均勻的三維微米／納米多孔結(jié)構(gòu)。所制備的三維微／納多孔金具有較大的表面積,具有多種功能：對葡萄糖的電催化氧化表現(xiàn)出較高的活性,可作為表面增強拉曼散射的基底,在修飾單層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.
【學位授予單位】：浙江師范大學
【學位級別】：碩士
【學位授予年份】：2011
【分類號】：TB383.1

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本文編號：2392119