多孔银的电催化性能研究

发布时间：2018-10-15 11:50

【摘要】：本文通过扫描电子显微镜、EDX能谱分析、电沉积技术等手段,循环伏安及恒电位等曲线的测定对多孔银电极(NPS)及铂微粒修饰多孔银电极(NPS-Pt)对甲醛及葡萄糖溶液的电催化氧化性能展开了一系列研究。结果表明:当多孔银电极在0.3 mol/L的HCHO溶液中,支持电解质KOH浓度为0.9 mol/L,扫描速度为20 mV/s时测得的甲醛的氧化峰电流密度最大且最稳定。随着循环次数的增加,多孔银电极表面发生了一定程度的粗化甚至球化,比表面积减小,导致催化活性降低。葡萄糖在纯银电极上的氧化包括在0.7 V左右AgO出现时的直接氧化以及在负向扫描过程中伴随着Ag2O出现时的逐渐氧化的过程。多孔银电极对葡萄糖的催化活性明显高于纯银电极。当支持电解液KOH浓度为0.1 mol/L,葡萄糖浓度在10 mmol/L-30mmol/L范围逐渐增大时,多孔银电极催化葡萄糖产生的氧化峰电流值也逐渐增大。随着循环次数的增多,多孔银电极催化葡萄糖的氧化峰电流密度逐渐减小,电极表面发生了粗化。在1 mmol/L H2PtCl6.6H2O+0.5 mol/L H2SO4溶液中对多孔银电极进行电沉积铂时,当沉积速度为10 mV/s,沉积圈数为5圈时,得到的铂微粒修饰多孔银电极对甲醛的催化氧化活性最高。整个电沉积过程及修饰电极对甲醛催化的动力学过程均受扩散控制。多孔银电极沉积铂后多孔的形貌并没有改变,能谱显示修饰电极铂含量为3.12%,沉积铂的总量约为100μg。对多孔银电极及其修饰电极对甲醛的电催化氧化活性及稳定性进行比较,测试结果表明:甲醛在修饰电极上氧化活化能低、反应速度快、活性高,稳定性也得到了明显的提高。
[Abstract]:In this paper, scanning electron microscopy, EDX energy spectrum analysis, electrodeposition technology and other means, Determination of cyclic voltammetry and potentiostatic curves the electrocatalytic oxidation properties of porous silver electrode (NPS) and platinum particle modified porous silver electrode (NPS-Pt) for formaldehyde and glucose solution were studied. The results show that the oxidation peak current density of formaldehyde is the largest and the most stable when the concentration of supporting electrolyte KOH is 0. 9 mol/L, and the scanning speed is 20 mV/s, when the porous silver electrode is in the HCHO solution of 0. 3 mol/L. With the increase of cycle times, the surface of porous silver electrode is coarsened or even spheroidized to a certain extent, and the specific surface area decreases, which leads to the decrease of catalytic activity. The oxidation of glucose on the sterling silver electrode includes the direct oxidation at about 0.7 V AgO and the gradual oxidation with the appearance of Ag2O in the negative scanning process. The catalytic activity of porous silver electrode for glucose was significantly higher than that of pure silver electrode. When the concentration of support electrolyte KOH was 0. 1 mol/L, glucose concentration increased in the range of 10 mmol/L-30mmol/L, the oxidation peak current value of glucose catalyzed by porous silver electrode increased gradually. With the increase of cycle times, the oxidation peak current density of glucose catalyzed by porous silver electrode decreases gradually and coarsening occurs on the electrode surface. When platinum was electrodeposited in 1 mmol/L H2PtCl6.6H2O 0.5 mol/L H2SO4 solution, the platinum particle modified porous silver electrode had the highest catalytic activity for formaldehyde oxidation when the deposition rate was 10 mV/s, and the number of cycles was 5 cycles. The whole electrodeposition process and the kinetic process of the modified electrode catalyzed by formaldehyde were controlled by diffusion. The morphology of the porous electrode was not changed after the deposition of platinum on the porous silver electrode. The platinum content of the modified electrode was 3.12 and the total amount of platinum deposited was about 100 渭 g. The electrocatalytic oxidation activity and stability of the porous silver electrode and its modified electrode for formaldehyde were compared. The results showed that the oxidation activation energy of formaldehyde on the modified electrode was low, the reaction rate was high, the activity was high, and the stability was improved obviously.
【学位授予单位】：大连交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.4;O614.122

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