Size Reduced Iron Nitroprusside Particles: an Electrochemical Mediator for the Quantification of Peroxodisulfate and Nitrite

Iron nitroprusside (FeNP) particles have been synthesized from drop by drop (n-FeNP) and bulk mixing (BM) (b-FeNP) methods. FeNP particles obtained from both methods were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). n-FeNP particles were used in constructing modified carbon paste electrode (CPE), which has been further used for electrochemical studies. The effect of pH and electrolyte cation on the electrochemical behavior of n-FeNP modified CPE has been studied in detail. Oxidation of nitrite and reduction of peroxodisulfate reactions have been electrocatalyzed at two redox centers of n-FeNP modified CPE. Based on the electrochemical experiments conducted and Tafel plots, mechanism for both the reactions has been proposed. Both the analytes were estimated in soil and ground water samples using n-FeNP modified CPE and the results were validated with the help of standard methods.

本研究通过逐滴法（制备n-FeNP）与本体混合法（bulk mixing, BM，制备b-FeNP）两种途径合成了硝普铁（Iron nitroprusside, FeNP）颗粒。采用X射线衍射（X-ray diffraction, XRD）与扫描电子显微镜（scanning electron microscopy, SEM）对两种方法制备得到的FeNP颗粒进行了表征。将逐滴法制备的n-FeNP颗粒用于构建修饰碳糊电极（modified carbon paste electrode, CPE），并将该修饰电极进一步应用于电化学研究。详细探究了pH值与电解质阳离子对n-FeNP修饰CPE电化学行为的影响。在n-FeNP修饰CPE的两个氧化还原中心处，可实现亚硝酸根的氧化与过二硫酸盐的还原电催化过程。基于开展的电化学实验与塔菲尔曲线（Tafel plots）分析，提出了上述两种反应的电催化机制。采用n-FeNP修饰CPE对土壤与地下水样品中的两种分析物进行了定量检测，并通过标准分析方法对检测结果进行了验证。