【摘要】：本文通過掃描電子顯微鏡、EDX能譜分析、電沉積技術等手段,循環(huán)伏安及恒電位等曲線的測定對多孔銀電極(NPS)及鉑微粒修飾多孔銀電極(NPS-Pt)對甲醛及葡萄糖溶液的電催化氧化性能展開了一系列研究。結果表明:當多孔銀電極在0.3 mol/L的HCHO溶液中,支持電解質KOH濃度為0.9 mol/L,掃描速度為20 mV/s時測得的甲醛的氧化峰電流密度最大且最穩(wěn)定。隨著循環(huán)次數(shù)的增加,多孔銀電極表面發(fā)生了一定程度的粗化甚至球化,比表面積減小,導致催化活性降低。葡萄糖在純銀電極上的氧化包括在0.7 V左右AgO出現(xiàn)時的直接氧化以及在負向掃描過程中伴隨著Ag2O出現(xiàn)時的逐漸氧化的過程。多孔銀電極對葡萄糖的催化活性明顯高于純銀電極。當支持電解液KOH濃度為0.1 mol/L,葡萄糖濃度在10 mmol/L-30mmol/L范圍逐漸增大時,多孔銀電極催化葡萄糖產生的氧化峰電流值也逐漸增大。隨著循環(huán)次數(shù)的增多,多孔銀電極催化葡萄糖的氧化峰電流密度逐漸減小,電極表面發(fā)生了粗化。在1 mmol/L H2PtCl6.6H2O+0.5 mol/L H2SO4溶液中對多孔銀電極進行電沉積鉑時,當沉積速度為10 mV/s,沉積圈數(shù)為5圈時,得到的鉑微粒修飾多孔銀電極對甲醛的催化氧化活性最高。整個電沉積過程及修飾電極對甲醛催化的動力學過程均受擴散控制。多孔銀電極沉積鉑后多孔的形貌并沒有改變,能譜顯示修飾電極鉑含量為3.12%,沉積鉑的總量約為100μg。對多孔銀電極及其修飾電極對甲醛的電催化氧化活性及穩(wěn)定性進行比較,測試結果表明:甲醛在修飾電極上氧化活化能低、反應速度快、活性高,穩(wěn)定性也得到了明顯的提高。
[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.
【學位授予單位】：大連交通大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB383.4;O614.122

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