Fischer Guntram, Poteau Romuald, Lachaize Sébastien, Gerber Iann C
Université de Toulouse; INSA, UPS, CNRS; LPCNO , 135 Avenue de Rangueil, 31077 Toulouse, France.
Langmuir. 2014 Oct 7;30(39):11670-80. doi: 10.1021/la502963n. Epub 2014 Sep 26.
Describing and understanding surface chemistry on the atomic scale is of primary importance in predicting and rationalize nanoparticle morphology as well as their physical and chemical properties. Here we present the results of comprehensive density functional theory studies on the adsorption of several small organic species, representing the major species (H2, Cl2, HCl, NH3, NH4Cl, and CH3COOH), present in the reaction medium during colloidal iron nanoparticle synthesis on various low-index iron surface models, namely, (100), (110), (111), (211), and (310). All of the tested ligands strongly interact with the proposed surfaces. Surface energies are calculated and ligand effects on the morphologies are presented, including temperature effects, based on a thermodynamic approach combined with the Wulff construction scheme. The importance of taking into account vibrational contributions during the calculation of surface energies after adsorption is clearly demonstrated. More importantly, we find that thermodynamic ligand effects can be ruled out as the unique driving force in the formation of recently experimentally observed iron cubic nanoparticles.
在原子尺度上描述和理解表面化学对于预测和合理化纳米颗粒的形态及其物理和化学性质至关重要。在此，我们展示了关于几种小有机物种吸附的综合密度泛函理论研究结果，这些物种代表了在胶体铁纳米颗粒合成过程中反应介质中存在的主要物种（H₂、Cl₂、HCl、NH₃、NH₄Cl和CH₃COOH），研究是在各种低指数铁表面模型上进行的，即(100)、(110)、(111)、(211)和(310)。所有测试的配体都与所提出的表面强烈相互作用。基于结合了伍尔夫构造方案的热力学方法，计算了表面能并展示了配体对形态的影响，包括温度效应。吸附后表面能计算过程中考虑振动贡献的重要性得到了明确证明。更重要的是，我们发现热力学配体效应不能被视为最近实验观察到的铁立方纳米颗粒形成的唯一驱动力。
