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首页> 外文期刊>The journal of physical chemistry, C. Nanomaterials and interfaces >Pt Degradation Mechanism in Concentrated Sulfuric Acid Studied Using Rotating Ring-Disk Electrode and Electrochemical Quartz Crystal Microbalance
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Pt Degradation Mechanism in Concentrated Sulfuric Acid Studied Using Rotating Ring-Disk Electrode and Electrochemical Quartz Crystal Microbalance

机译：旋转圆盘电极和电化学石英晶体微天平研究浓硫酸中铂的降解机理

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In this paper, we describe our electrochemical investigation of platinum degradation in concentrated sulfuric acid. The Pt electrode weight is found to decrease by an alternating potential cycle between <-0.5 V vs Ag2SO4 and > +0.5 V vs Ag/Ag2SO4. No marked weight decrease occurs by excluding the former or latter region. Also, electrochemical reactions that participate in Pt dissolution and occur between the two potential regions were studied by a rotating ring-disk electrode (RRDE) method. The obtained voltammogram indicates (i) the electrodeposition of sulfur at <-0.5 V vs Ag/Ag2SO4, (ii) the dissolution of sulfur at (+0.6)-(+0.8) V vs Ag/Ag2SO4, (iii) the formation of a precursor to Pt dissolution at (+0.9)-(+1.2) V vs Ag/Ag2SO4, and (iv) Pt dissolution at +0.5 V vs Ag/Ag2SO4. Then, (v) the dissolved Pt is reduced at -0.2 V vs Ag/Ag2SO4. Further investigation was conducted to elucidate the relationships between each reaction by employing an electrochemical quartz crystal microbalance (EQCM). Consequently, the amount of sulfur dissolution at (+0.6)-(+0.8) V vs Ag/Ag2SO4 in step ii affects the amount of subsequent precursor formed that causes Pt dissolution in step iii. A large amount of precursor formed results in a large amount of Pt dissolving at around +0.5 V vs Ag/Ag2SO4 in step iv. These results strongly indicate that the deposition and dissolution of sulfur affect the amount of precursor formed that causes Pt dissolution. After a 30 h potential -sweep, which ensured the corrosion of Pt, no dissolved Pt was found in the electrolytic solution, but Pt deposited on the electrode as metallic Pt in particle form. These phenomena imply that the dissolved Pt in step iv then deposits in the neighborhood of the Pt surface in step v. The dependence of Pt degradation on the electrode potential was clearly explained by the results of RRDE and EQCM measurements.
机译：在本文中，我们描述了我们在浓硫酸中降解铂的电化学研究。发现Pt电极的重量在相对于Ag2SO4的--0.5 V和相对于Ag / Ag2SO4的+0.5 V的交替电势周期内降低。通过排除前一个或后一个区域，重量不会显着降低。此外，通过旋转环盘电极（RRDE）方法研究了参与Pt溶解并在两个电位区域之间发生的电化学反应。所得的伏安图表明（i）相对于Ag / Ag2SO4在<-0.5 V下电沉积硫，（ii）相对于Ag / Ag2SO4在（+0.6）-（+ 0.8）V下硫的溶解，（iii）相对于Ag / Ag2SO4在（+0.9）-（+ 1.2）V下Pt溶解的前体，和（Ag）对Ag / Ag2SO4在+0.5 V上Pt溶解。然后，（v）相对于Ag / Ag 2 SO 4在-0.2V下还原溶解的Pt。通过使用电化学石英晶体微量天平（EQCM）进行了进一步的研究，以阐明每个反应之间的关系。因此，在步骤ii中，在（+0.6）-（+ 0.8）V处相对于Ag / Ag2SO4的硫溶解量影响了在步骤iii中导致Pt溶解的随后形成的前体的量。在步骤iv中，形成的大量前驱物导致大量Pt在相对于Ag / Ag2SO4的+0.5 V左右溶解。这些结果强烈表明硫的沉积和溶解会影响所形成的导致Pt溶解的前体的数量。经过30小时的电位扫描（确保了Pt的腐蚀）后，在电解液中没有发现溶解的Pt，但是Pt以颗粒形式的金属Pt沉积在电极上。这些现象表明，步骤iv中溶解的Pt然后在步骤v中沉积在Pt表面附近。RRDE和EQCM测量结果清楚地说明了Pt降解对电极电势的依赖性。

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