Chemisorption of Hydroxide on 2D Materials from DFT Calculations: Graphene versus Hexagonal Boron Nitride.
Chemisorption of Hydroxide on 2D Materials from DFT Calculations: Graphene versus Hexagonal Boron Nitride.
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DOI：
10.1021/acs.jpclett.6b02248
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发表时间：
2016-11-17
期刊：
影响因子：
--
通讯作者：
Bocquet ML
中科院分区：
文献类型：
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作者：
Grosjean B;Pean C;Siria A;Bocquet L;Vuilleumier R;Bocquet ML
最近的nanofluidic测量揭示了强烈不同的表面电荷测量氮化硼和石墨纳米管接触时，与盐水和碱性水。这些观察结果与石墨烯层及其氮化硼对应物的类似反应性形成对比，使用密度泛函理论（DFT）框架，用于气态水分子的完整和解离吸附。在这里，我们调查，通过DFT在隐式水，单和多个吸附的阴离子氢氧化物在单层。在真空中发现了两种材料上的第一离子吸附的差异吸附强度-化学吸附在BN上，而物理吸附在石墨烯上。隐式溶剂化的影响降低了所有吸附值，导致BN（石墨烯）上的有利（不利）吸附。我们还计算了BN在水中的pKa为1.6，与实验结果吻合良好。相比之下，石墨烯在水中的不利结果反映了较弱的表面电荷测量结果，但指出了另一种情况。
Recent nanofluidic measurements revealed strongly different surface charge measurements for boron-nitride and graphitic nanotubes when in contact with saline and alkaline water. These observations contrast with the similar reactivity of a graphene layer and its boron nitride counterpart, using Density Functional Theory (DFT) framework, for intact and dissociative adsorption of gaseous water molecules. Here, we investigate, by DFT in implicit water, single and multiple adsorption of anionic hydroxide on single layers. A differential adsorption strength is found in vacuum for the first ionic adsorption on the two materials – chemisorbed on BN while physisorbed on graphene. The effect of implicit solvation reduces all adsorption values resulting in a favorable (non-favorable) adsorption on BN (graphene). We also calculate a pKa ≃ 6 for BN in water, in good agreement with experiments. Comparatively, the unfavorable results for graphene in water echoes the weaker surface charge measurements, but points to an alternative scenario.