Lévy Anna, De Anda Villa Manuel, Laurens Gaétan, Blanchet Valérie, Bozek John, Gaudin Jérôme, Lamour Emily, Macé Stéphane, Mignon Pierre, Milosavljević Aleksandar R, Nicolas Christophe, Patanen Minna, Prigent Christophe, Robert Emmanuel, Steydli Sébastien, Trassinelli Martino, Vernhet Dominique, Veteläinen Onni, Amans David
Institut des Nanosciences de Paris, Sorbonne Université, Campus Pierre et Marie Curie, CNRS UMR7588, 75005 Paris, France.
Université Claude Bernard Lyon 1, UMR5306 CNRS, Institut Lumière Matière, University of Lyon, F-69622 Villeurbanne, France.
Langmuir. 2021 May 18;37(19):5783-5794. doi: 10.1021/acs.langmuir.1c00092. Epub 2021 May 3.
Pulsed laser ablation in liquid (PLAL) is a powerful method for producing nanoparticle colloids with a long-term stability despite the absence of stabilizing organic agents. The colloid stability involves different reactivities and chemical equilibria with complex ionic-specific effects at the nanoparticle/solvent interface which must be strongly influenced by their chemical composition. In this work, the surface composition of PLAL-produced gold nanoparticles in alkaline and saline (NaBr) water is investigated by X-ray photoelectron spectroscopy on free-flying nanoparticles, exempt from any substrate or radiation damage artifact. The Au 4f photoelectron spectra with a depth profiling investigation are used to evaluate the degree of nanoparticle surface oxidation. In alkaline water, the results preclude any surface oxidation contrary to the case of nanoparticles produced in NaBr solution. In addition, the analysis of Br 3d core-level photoelectron spectra agrees with a clear signature of Br on the nanoparticle surface, which is confirmed by a specific valence band feature. This experimental study is supported by DFT calculations, evaluating the energy balance of halide adsorption on different configurations of gold surfaces including oxidation or adsorbed salts.
液体中的脉冲激光烧蚀（PLAL）是一种强大的方法，可用于制备具有长期稳定性的纳米颗粒胶体，即使不存在稳定的有机试剂。胶体稳定性涉及纳米颗粒/溶剂界面处具有复杂离子特异性效应的不同反应性和化学平衡，这些效应必然受到其化学成分的强烈影响。在这项工作中，通过对自由飞行的纳米颗粒进行X射线光电子能谱研究，研究了在碱性和盐水（NaBr）水中PLAL制备的金纳米颗粒的表面组成，该研究不受任何基底或辐射损伤假象的影响。具有深度剖析研究的Au 4f光电子能谱用于评估纳米颗粒表面氧化程度。在碱性水中，结果排除了任何表面氧化，这与在NaBr溶液中产生的纳米颗粒的情况相反。此外，对Br 3d芯能级光电子能谱的分析与纳米颗粒表面上Br的清晰特征一致，这通过特定的价带特征得到证实。这项实验研究得到了密度泛函理论（DFT）计算的支持，该计算评估了卤化物在包括氧化或吸附盐在内的不同金表面构型上吸附的能量平衡。
