Reduction of NO adlayers on Pt(110) and Pt(111) in acidic media: evidence for adsorption site-specific reduction.
Reduction of NO adlayers on Pt(110) and Pt(111) in acidic media: evidence for adsorption site-specific reduction.
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DOI：
10.1021/la0475831
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发表时间：
2005-02
期刊：
影响因子：
--
通讯作者：
V. Rosca;G. Beltramo;M. Koper
中科院分区：
文献类型：
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作者：
V. Rosca;G. Beltramo;M. Koper
我们提出了一种结合原位傅里叶变换红外反射吸收光谱和伏安法的研究方法，研究了酸性介质中Pt（111）和Pt（110）单晶表面饱和和亚饱和NO掺杂物的还原。溶出伏安实验和相关的红外光谱演化表明，在所考虑的表面上电化学还原NO（ads）的伏安谱中观察到的不同特征（峰）与不同吸附位点的NO（ads）还原有关，而与不同（连续）过程无关。更具体地说，Pt（110）上高覆盖度和中等覆盖度（约0.5-1单层（ML）） NO层的减少伴随着位置从顶部切换到桥接位置，这与超高真空数据一致。在Pt（111）上，线性键合（顶部）NO和面心立方3倍中空NO在高覆盖率（0.25 ~ 0.5 ML）下共存，并且可以连续独立地还原。在Pt（111）和Pt（110）电极上，线性键合的NO比多重键合的NO反应性更强。光谱和伏安数据都表明，氨是两个表面上NO（ads）还原的主要产物。
We present a combined in situ Fourier transform infrared reflection-absorption spectroscopy and voltammetric study of the reduction of saturated and subsaturated NO adlayers on Pt(111) and Pt(110) single-crystal surfaces in acidic media. The stripping voltammetry experiments and the associated evolution of infrared spectra indicate that different features (peaks) observed in the voltammetric profile for the electrochemical reduction of NO adlayers on the surfaces considered are related to the reduction of NO(ads) at different adsorption sites and not to different (consecutive) processes. More specifically, reduction of high- and intermediate-coverage (ca. 0.5-1 monolayers (ML)) NO adlayers on Pt(110) is accompanied by site switching from atop to bridge position, in agreement with the ultra-high-vacuum data. On Pt(111) linearly bonded (atop) NO and face-centered cubic 3-fold-hollow NO species coexist at high coverages (0.25-0.5 ML) and can be reduced consecutively and independently. On Pt(111) and Pt(110) electrodes, linearly bonded NO species are more reactive than multifold-bonded NO species. Both spectroscopic and voltammetric data indicate that ammonia is the main product of NO(ads) reduction on the two surfaces examined.