The adsorption from a solution of s-1-(1-naphthyl)ethylamine (s-NEA), cinchonidine, and cinchonine on Pt/SiO₂, Pt/Al₂O₃, and a Pt disk was probed in situ by infrared absorption spectroscopy. Adsorption on the supported catalysts shows similar behavior to that seen on flat polycrystalline Pt surfaces, with the adsorption geometry transitioning from the aromatic ring lying close to parallel to the metal surface at low coverages to a more tilted geometry at monolayer saturation. The extent of the adsorption of the chiral modifiers and its degree of irreversibility both vary with the nature of the liquid (CCl₄, toluene, ethanol), tracking solubility. Carbon monoxide can be coadsorbed with s-NEA, a coadsorption that leads to a compression and an increase in ordering of the s-NEA layer (aided by exposing the surface to H₂). In contrast, s-NEA adsorption dominates when competing with quinoline. Finally, a few small differences were seen in the IR spectra of the chiral modifiers adsorbed on Pt/SiO₂ (compared to the other solids) because of the smaller size of the Pt nanoparticles associated with that catalyst. In general, it is crucial to characterize the adsorption of chiral modifiers in situ in the presence of the liquid phase, but the contribution from the catalyst support appears to be minor.

中文翻译：

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手性改性剂从溶液到负载型铂催化剂的吸附：溶剂，其他共吸附物和载体的影响

通过红外吸收原位检测s-1-（1-萘基）乙胺（s-NEA），辛可尼定和辛可宁在Pt / SiO ₂，Pt / Al ₂ O ₃和Pt盘上的吸附光谱学。在负载型催化剂上的吸附表现出与在平坦多晶Pt表面上看到的相似的行为，吸附几何形状从低覆盖率的芳香环几乎平行于金属表面过渡到单层饱和时更倾斜的几何形状。手性改性剂的吸附程度及其不可逆度均随液体的性质（CCl ₄，甲苯，乙醇），跟踪溶解度。一氧化碳可以与s-NEA共吸附，共吸附会导致s-NEA层压缩和顺序增加（通过将表面暴露于H ₂来辅助）。相反，当与喹啉竞争时，s-NEA吸附占主导。最后，由于与该催化剂相关的Pt纳米粒子的尺寸较小，因此吸附在Pt / SiO ₂上的手性改性剂的红外光谱（与其他固体相比）存在一些小的差异。通常，至关重要的是表征在液相存在下原位手性改性剂的吸附特性，但是催化剂载体的贡献似乎很小。