Role of electron localisation in H adsorption and hydride formation in the Mg basal plane under aqueous corrosion: a first-principles study.
Role of electron localisation in H adsorption and hydride formation in the Mg basal plane under aqueous corrosion: a first-principles study.
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水腐蚀下镁基面电子局域化在 H 吸附和氢化物形成中的作用：第一性原理研究。
DOI：
10.1039/d2cp05242c
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Li B
中科院分区：
文献类型：
--
作者：
Li B
了解氢-金属相互作用在表面科学的各个领域都很重要，包括金属的水腐蚀。氢原子与Mg表面的相互作用是形成亚表面氢化物的关键过程，在Mg水溶液腐蚀中起着重要作用。在本工作中，我们采用第一性原理密度泛函理论（DFT）计算来研究水条件下氢吸附和结晶氢化物形成的机理。发现电子定位函数（ELF）是预测氢在镁表面稳定吸附的一个有希望的指标。发现氢吸附和氢化物层的形成以高极低频吸附位点为主。我们的计算表明，原子H、OH自由基和原子O的表面吸附可以增强电子在亚表面区域特定位置的定位，从而在局部形成有效的H陷阱。预计这将导致形成热力学稳定的亚表面氢化物层，这是镁的关键氢化物腐蚀产物的潜在前体。
Understanding hydrogen-metal interactions is important in various fields of surface science, including the aqueous corrosion of metals. The interaction between atomic H and a Mg surface is a key process for the formation of sub-surface Mg hydride, which may play an important role in Mg aqueous corrosion. In the present work, we performed first-principles Density Functional Theory (DFT) calculations to study the mechanisms for hydrogen adsorption and crystalline Mg hydride formation under aqueous conditions. The Electron Localisation Function (ELF) is found to be a promising indicator for predicting stable H adsorption in the Mg surface. It is found that H adsorption and hydride layer formation is dominated by high ELF adsorption sites. Our calculations suggest that the on-surface adsorption of atomic H, OH radicals and atomic O could enhance the electron localisation at specific sites in the sub-surface region, thus forming effective H traps locally. This is predicted to result in the formation of a thermodynamically stable sub-surface hydride layer, which is a potential precursor of the crucial hydride corrosion product of magnesium.