Formation of Pt Skin Layer on Ordered and Disordered Pt-Co Alloys and Corrosion Resistance in Sulfuric Acid
Formation of Pt Skin Layer on Ordered and Disordered Pt-Co Alloys and Corrosion Resistance in Sulfuric Acid
复制标题
DOI：
10.1007/s12678-017-0448-9
复制
发表时间：
2018-09
期刊：
影响因子：
3.1
通讯作者：
Y. Sugawara;M. Konno;I. Muto;N. Hara
中科院分区：
文献类型：
--
作者：
Y. Sugawara;M. Konno;I. Muto;N. Hara
研究了脱合金化处理在有序和无序的铂钴合金表面形成的富铂层(铂表层)的形成及其在硫酸中的耐蚀性，以阐明铂表层在聚合物电解质燃料电池运行条件下的溶解行为。分别在1073K和1473K下进行热处理，得到有序和无序的铂钴样品。298K时，在自然曝气的0.5M H_2SO_4中，合金表面的CO在脱合金处理的早期阶段显著溶解，并形成了铂表层。在0.5M的H_2SO_4中进行脱合金化处理后，在铂钴合金表面形成了厚度约为2单层的铂表层。循环伏安测试表明，脱合金化处理后的铂表层的存在，抑制了铂表层上铂氧化物的生成。有序的铂钴比无序的铂钴更能抑制铂氧化物的生成。在0.5M的H_2SO_4溶液中，在0.6-1.4V的电位范围内，有序的铂-钴的铂表层的溶解比无序的铂-钴的铂表层的溶解受到更大的抑制(溶解试验)。经溶解测试后，有序的铂-钴样品表面仍有一层薄的、连续的铂表层。与无序的铂-钴和纯的铂相比，有序的铂-钴的铂表层的溶解受到了高度的抑制。铂氧生成的抑制似乎是耐蚀性较高的主要原因。薄而连续的铂表层的形成对于防止铂的溶解是重要的。
The formation of the Pt-enriched layer (Pt skin layer) formed at the surface of the ordered and disordered Pt-Co alloy specimens by a dealloying treatment and its corrosion resistance under potential cycling in sulfuric acid were examined to clarify the dissolution behavior of the Pt skin layer in polymer electrolyte fuel cell-operating conditions. The ordered and disordered Pt-Co specimens were obtained by heat treatment at 1073 and 1473 K, respectively. Co at the alloy surfaces dramatically dissolved in an early phase of the dealloying treatment in naturally aerated 0.5 M H2SO4at 298 K, and Pt skin layers were formed. Pt skin layers ca.2 monolayer in thickness were formed on the Pt-Co alloy specimens by the dealloying treatment in 0.5 M H2SO4. The cyclic voltammetry measurements of the Pt-Co specimens showed the existence of Pt skin layers after the dealloying treatment and the inhibition of the Pt oxide formation on the Pt skin layers. The Pt oxide formation for ordered Pt-Co was more suppressed than that for the disordered Pt-Co. The Pt skin layers on the Pt-Co specimens exhibited a higher corrosion resistance than pure Pt, and the dissolution of the Pt skin layer for ordered Pt-Co was more inhibited than that for disordered Pt-Co under potential cycling in the potential range of 0.6–1.4 V in 0.5 M H2SO4(dissolution test). A thin, continuous Pt skin layer remained at the surface of the ordered Pt-Co specimen after the dissolution test. The formation of a uniform Pt skin layer seems to provide high oxidation resistance to the surface, leading to high corrosion resistance.Graphical AbstractThe dissolution of Pt skin layer for the ordered Pt-Co was highly suppressed compared with that for the disordered Pt-Co and pure Pt. The suppression of Pt-O formation seems to be the main reason for the high corrosion resistance. The formation of a thin and continuous Pt skin layer is important to prevent the dissolution of Pt.