Insight into Subsurface Adsorption Derived from a Lattice-Gas Model and Monte Carlo Simulations
Insight into Subsurface Adsorption Derived from a Lattice-Gas Model and Monte Carlo Simulations
复制标题
DOI：
10.1021/acs.jpcc.2c00342
复制
发表时间：
2022-03
期刊：
影响因子：
--
通讯作者：
Carson J Mize;Lonnie D. Crosby;Sara B. Isbill;Sharani Roy
中科院分区：
文献类型：
--
作者：
Carson J Mize;Lonnie D. Crosby;Sara B. Isbill;Sharani Roy
描述在广泛的吸附质浓度范围内的吸附的理论气体表面模型可以提供对化学现象的定性洞察，例如表面下吸附、表面重建和工业多相催化。然而，大多数原子，气体表面吸附的量子力学模型是有限的低吸附覆盖率，由于大量的计算成本的模型建立使用许多表面原子和吸附物。为了研究吸附在地下的结晶固体覆盖率增加，我们提出了一个晶格气体吸附模型，包括表面和地下网站的固体和完全参数化使用密度泛函理论。我们应用该模型研究了原子氧在Ag（111）表面的表面吸附和亚表面吸附之间的竞争。使用该模型结合Monte Carlo模拟计算的氧人口分布显示发病的总覆盖率为0.375单层以上的次表面吸附和更大的积累的氧在第二次比在第一次表面在总覆盖率为0.5和1单层。我们的模拟还表明，氧原子不渗透到散装区域的银的总覆盖率高达1个单层，表明吸附在次表面的氧是不同的氧吸收在该覆盖范围内的散装。核心电子结合能和投影态密度的平衡氧分布在0.5单层的计算揭示在表面和次表面的氧-银键合的定性差异，这表明在两个区域中吸附的氧可以发挥不同的作用，在表面化学。
Theoretical gas-surface models that describe adsorption over a broad range of adsorbate concentrations can provide qualitative insight into chemical phenomena, such as subsurface adsorption, surface reconstruction, and industrial heterogeneous catalysis. However, most atomistic, quantum-mechanical models of gas-surface adsorption are limited to low adsorbate coverage due to the large computational cost of models built using many surface atoms and adsorbates. To investigate adsorption in the subsurface of a crystalline solid with increasing coverage, we present a lattice-gas adsorption model that includes surface and subsurface sites of the solid and is fully parametrized using density functional theory. We apply the model to study the competition between the surface and subsurface adsorption of atomic oxygen on the Ag(111) surface. Oxygen population distributions calculated using the model in combination with Monte Carlo simulations show the onset of subsurface adsorption above a total coverage of 0.375 monolayer and a greater accumulation of oxygen in the second than in the first subsurface at total coverages between 0.5 and 1 monolayer. Our simulations also show that oxygen atoms do not percolate into the bulk region of silver for total coverages of up to 1 monolayer, indicating that oxygen adsorbed in the subsurface is distinct from oxygen absorbed in the bulk in this coverage range. Computations of core–electron binding energies and projected density of states for the equilibrium oxygen distribution at 0.5 monolayer reveal qualitative differences in the oxygen–silver bonding at the surface and subsurface, suggesting that oxygen adsorbed in the two regions could play distinct roles in the surface chemistry.