A Surface‐Enhanced Raman Spectroscopy Study on Adsorption of Some Sulfur‐Containing Corrosion Inhibitors on Iron in Hydrochloric Acid Solutions
A Surface‐Enhanced Raman Spectroscopy Study on Adsorption of Some Sulfur‐Containing Corrosion Inhibitors on Iron in Hydrochloric Acid Solutions
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DOI：
10.1149/1.2085398
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发表时间：
1991-11
影响因子：
3.9
通讯作者：
J. Uehara;K. Aramaki
中科院分区：
文献类型：
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作者：
J. Uehara;K. Aramaki
用表面增强拉曼散射（Sers）光谱研究了苯乙烷、苯甲烷乙烷和甲基苯硫醚在0.5M盐酸和0.1M氯化钾溶液中的吸附模式。这些化合物吸附在铁上的光谱测量使用银电极完全覆盖的电沉积铁层。苯乙烷和苯甲烷乙烷的Sers光谱没有显示吸附在铁表面的物种的S-H键。结果表明，在两种溶液中，所有化合物均化学吸附在铁表面，前两种缓蚀剂的硫醇根离子是通过硫原子与铁原子之间形成较强的~-键而吸附的，因此它们的缓蚀效率高于甲基苯硫醚。在0.5M HCl中，在铁表面上不发生锍阳离子的静电吸附。除了化学吸附B~-外，表面与苯乙撑或甲基苯硫醚的芳环之间还发生~-电子相互作用.在0.1 M KCl溶液中，用表面增强拉曼散射研究了吡啶和N-乙基溴化吡啶在铁表面的吸附行为.使用完全覆盖有最小厚度的铁层（5个单层，约100 μ m）的SERS活性银电极检测到吸附在铁表面上的吡啶的强烈Sers信号。1.4平均值）。一些氮化合物在0.5 M HCl中在铁表面的吸附和取向模式也已通过Sers光谱测定（3，4）。讨论了这些化合物在酸性溶液中对铁的缓蚀作用。许多有机硫化合物被认为是酸溶液中各种金属的有效缓蚀剂（5-7）。它们中的一些在金属表面发生反应，其反应产物被吸附在表面上，从而抑制金属腐蚀（8-11）。含硫化合物的Sers测量似乎适合于研究抑制机理，包括反应产物在表面上的吸附。在本研究中，在0.1 M KCl（pH 3.5）和0.5 M HCl中，用覆盖有沉积铁的SERS活性银电极测量了吸附在铁上的苯硫基、苯甲烷硫醇和甲基苯硫醚的Sers光谱。根据Sers光谱和极化曲线，讨论了这些化合物的吸附行为和缓蚀效果的差异。
The adsorption modes of some sulfur compounds, benzenethiol, phenylmethanethiol, and methyl phenyl sulfide on iron in 0.1 M KC1 at pH 3.5 and 0.5 M HC1 were investigated by surface-enhanced Raman scattering (SERS) spectroscopy. Spectra of these compounds adsorbed on iron were measured using a silver electrode completely covered with an electrodeposited iron layer. The SERS spectra of benzenethiol and phenylmethanethiol did not show S--H bonds for the species adsorbed on the iron surface in the solutions. It is concluded that all the compounds are chemisorbed on the iron surface in both solutions, and that thiolate ions of the former two inhibitors are adsorbed by the formation of stronger~-bonds between sulfur and iron atoms, resulting in higher inhibition efficiencies for these compounds than for methyl phenyl sulfide. No electrostatic adsorption of the sulfonium cation occurs on the iron surface in 0.5 M HC1. In addition to the chemical adsorption b~ the formation of a a-bond,~-electron interaction takes place between the surface and an aromatic ring of benzenethiol or methyl phenyl sulfide.Previous papers (1, 2) have dealt with surface-enhanced Raman scattering studies on the adsorption behavior of pyridine and N-ethyl-pyridinium bromide on iron in a 0.1 M KC1 solution. Intense SERS signals of pyridine adsorbed on the iron surface have been detected using a SERS-active silver electrode completely covered with an iron layer of minimum thickness (5 monolayers, ca. 1.4 nm on the average). The adsorption and orientation modes of some nitrogen compounds at the iron surface in 0.5 M HCI have also been determined by SERS spectroscopy (3, 4). Inhibition effects of these compounds on iron corrosion in the acid solution have been discussed. A number of organic sulfur compounds are known as effective corrosion inhibitors for various metals in acid solutions (5-7). Some of them react at the metal surface and their reaction products are adsorbed on the surface, resulting in inhibition of metallic corrosion (8-11). The SERS measurement of sulfur compounds seems appropriate for investigating the inhibition mechanism, including the adsorption of reaction products on the surface. In this study, the SERS spectra of benzenethio], phenylmethanethiol, and methyl phenyl sulfide adsorbed on iron in 0.1 M KC1 at pH 3.5 and 0.5 M HC1 were measured with a SERS-active silver electrode covered with deposited iron. Differences in the adsorption behavior and corrosion inhibition effectiveness of these compounds are discussed based on the SERS spectra and polarization curves.