When more is less: Nonmonotonic trends in adsorption on clusters in alloy surfaces
When more is less: Nonmonotonic trends in adsorption on clusters in alloy surfaces
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DOI：
10.1063/5.0022076
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发表时间：
2020-09-21
影响因子：
4.4
通讯作者：
Montemore, Matthew M.
中科院分区：
文献类型：
--
作者：
Monasterial, Abigale P.;Hinderks, Calla A.;Montemore, Matthew M.
单原子合金可以是有效的催化剂，并已与负载型单原子催化剂进行了比较。为了合理地设计单原子合金和其他具有局部系综的表面，关键是要了解当改变掺杂剂和系综尺寸时反应性的变化。在这里，我们研究了嵌入本地集群的表面上的氢吸附，并发现了一般的趋势。与直觉相反，增加活性更高的金属的量有时会使表面部位的活性降低。这种行为是由于许多这些表面的电子态密度中的窄峰的杂化和分裂，使它们类似于独立的纳米团簇。当单原子合金具有刚好低于费米能的峰时，由于该峰在费米能上分裂，相应的双掺杂剂簇通常具有比单原子合金更弱的吸附。此外，单原子合金与更大的系综相比具有质的不同行为。具体地说，吸附能是一个U形函数的掺杂剂的单原子合金的基团。此外，单原子合金上的吸附能与掺杂剂的p带中心比与d带中心的相关性更强。
Single-atom alloys can be effective catalysts and have been compared to supported single-atom catalysts. To rationally design single-atom alloys and other surfaces with localized ensembles, it is crucial to understand variations in reactivity when varying the dopant and the ensemble size. Here, we examined hydrogen adsorption on surfaces embedded with localized clusters and discovered general trends. Counterintuitively, increasing the amount of a more reactive metal sometimes makes a surface site less reactive. This behavior is due to the hybridization and splitting of narrow peaks in the electronic density of states of many of these surfaces, making them analogous to free-standing nanoclusters. When a single-atom alloy has a peak just below the Fermi energy, the corresponding two-dopant cluster often has weaker adsorption than the single-atom alloy due to splitting of this peak across the Fermi energy. Furthermore, single-atom alloys have qualitatively different behaviors than larger ensembles. Specifically, the adsorption energy is a U-shaped function of the dopant's group for single-atom alloys. Additionally, adsorption energies on single-atom alloys correlate more strongly with the dopant's p-band center than with the d-band center.