Réocreux R, Girel É, Clabaut P, Tuel A, Besson M, Chaumonnot A, Cabiac A, Sautet P, Michel C
Univ Lyon, Ens de Lyon, CNRS UMR 5182, Université Claude Bernard Lyon 1, Laboratoire de Chimie, 69342, Lyon, France.
Thomas Young Centre and Department of Chemical Engineering, University College London, Roberts Building, Torrington Place, London, WC1E 7JE, UK.
Nat Commun. 2019 Jul 17;10(1):3139. doi: 10.1038/s41467-019-10981-9.
The kinetic stability of any material in water relies on the presence of surface weak spots responsible for chemical weathering by hydrolysis. Being able to identify the atomistic nature of these sites and the first steps of transformation is therefore critical to master the decomposition processes. This is the challenge that we tackle here: combining experimental and modeling studies we investigate the stability of alumina in water. Exploring the reactivity of shape-controlled crystals, we identify experimentally a specific facet as the location of the weak spots. Using biased ab initio molecular dynamics, we recognize this weak spot as a surface exposed tetra-coordinated Al atom and further provide a detailed mechanism of the first steps of hydrolysis. This understanding is of great importance to heterogeneous catalysis where alumina is a major support. Furthermore, it paves the way to atomistic understanding of interfacial reactions, at the crossroad of a variety of fields of research.
任何材料在水中的动力学稳定性都依赖于表面弱点的存在，这些弱点是由水解作用导致化学风化的原因。因此，能够识别这些位点的原子性质以及转化的第一步对于掌握分解过程至关重要。这就是我们在此要解决的挑战：通过结合实验和建模研究，我们研究了氧化铝在水中的稳定性。通过探索形状可控晶体的反应性，我们通过实验确定了一个特定晶面是弱点所在位置。使用有偏的从头算分子动力学，我们将这个弱点识别为表面暴露的四配位铝原子，并进一步提供了水解第一步的详细机制。这种理解对于氧化铝作为主要载体的多相催化非常重要。此外，它为在各种研究领域的交叉点上对界面反应进行原子层面的理解铺平了道路。
