碱性溶液中BH-4的电化学氧化机理及伏安法测定

Oxidation Process and Concentration Determination of BH-4 in Alkaline Solution

中文关键词:  NaBH₄  Au电极  电分析  伏安法

英文关键词:Sodium borohydride  Au electrode  Voltammetry  Electroanalysis

中文摘要:

      对比NaBH₄碱性溶液Cu、Ag、Ni、Pt和Au电极的循环伏安特性发现,BH-₄在Au电极上活性最强,Pt有一定的活性,而Cu、Ag及Ni几乎没有活性。用三电极体系研究了BH-₄在Au电极上的氧化机理,分析了碱性体系中不同浓度NaBH₄溶液的线性循环伏安特性,讨论了扫描速度、OH-和B(OH)-₄浓度等对BH-₄氧化峰电位及峰电流的影响。结果表明,以Au电极为工作电极的峰值电流法是BH-₄离子定性和定量检测的一种简单、快速、准确的方法。同时,溶液中较大浓度范围内变化的OH-和B(OH)-₄对NaBH₄的分析无明显影响。

英文摘要:

      :The electrochemical oxidation of NaBH₄ on Au,Pt,Ni,Ag,Cu and Ni electrodes were taken into consideration.The most effective metal for BH-₄ oxidation was found to be Au.Pt electrodes also showed certain activity while,Ni,Ag and Cu were not effective.Electrochemical oxidation reaction of borohydride is a complicated irreversible oxidation process,the electrochemical oxidation behavior of NaBH₄ on Au electrode was analyzed by cyclic voltammetry.The results showed that,the BH-₄ can be indicated as low as 10-5mol/L,and a linear dependence between the oxidation peak formed by NaBH₄ direct oxidation and the concentration of NaBH₄ was presented in the concentration range from 1×10-4 to 1×10-2mol/L,which can used as a quantity electroanalysis method for BH-₄.The effect of electrode area,concentration of OH- and B(OH)₄- were taken into consideration,a larger area Au electrode shows more excellent performance in both the accuracy and the detection limit,both the concentration of OH- and B(OH)-₄with little effect on the BH-₄quantitative analysis at a certain concentration range.This established electroanalysis method could be used to determine the NaBH₄ concentration (especially in the process of electrochemical hydroboration) quickly and with excellent reproducibility and good accuracy.