Monet Geoffrey, Paineau Erwan, Chai Ziwei, Amara Mohamed S, Orecchini Andrea, Jimenéz-Ruiz Mónica, Ruiz-Caridad Alicia, Fine Lucas, Rouzière Stéphan, Liu Li-Min, Teobaldi Gilberto, Rols Stéphane, Launois Pascale
Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris-Saclay 91405 Orsay Cedex France
Beijing Computational Science Research Centre 100193 Beijing China
Nanoscale Adv. 2020 Apr 13;2(5):1869-1877. doi: 10.1039/d0na00128g. eCollection 2020 May 19.
By combined use of wide-angle X-ray scattering, thermo-gravimetric analysis, inelastic neutron scattering, density functional theory and density functional theory molecular dynamics simulations, we investigate the structure, dynamics and stability of the water wetting-layer in single-walled aluminogermanate imogolite nanotubes (SW Ge-INTs): an archetypal system for synthetically controllable and monodisperse nano-reactors. We demonstrate that the water wetting-layer is strongly bound and solid-like up to 300 K under atmospheric pressure, with dynamics markedly different from that of bulk water. Atomic-scale characterisation of the wetting-layer reveals organisation of the HO molecules in a curved triangular sublattice stabilised by the formation of three H-bonds to the nanotube's inner surface, with covalent interactions sufficiently strong to promote energetically favourable decoupling of the HO molecules in the adlayer. The evidenced changes in the local composition, structure, electrostatics and dynamics of the Ge-INT's inner surface upon the formation of the solid wetting-layer demonstrate solvent-mediated functionalisation of the nanotube's cavity at room temperature and pressure, suggesting new strategies for the design of nano-rectors towards potential control of chemical reactivity in nano-confined volumes.
通过结合使用广角X射线散射、热重分析、非弹性中子散射、密度泛函理论和密度泛函理论分子动力学模拟，我们研究了单壁铝锗伊莫戈石纳米管（SW Ge-INTs）中水润湿层的结构、动力学和稳定性：这是一个用于合成可控且单分散的纳米反应器的典型系统。我们证明，在大气压力下，水润湿层在高达300 K时强烈结合且类似固体，其动力学与 bulk 水明显不同。对润湿层的原子尺度表征揭示了HO分子在弯曲的三角形亚晶格中的排列，该亚晶格通过与纳米管内表面形成三个氢键而稳定，共价相互作用足够强，以促进吸附层中HO分子在能量上有利的解耦。在形成固体润湿层时，Ge-INT内表面的局部组成、结构、静电和动力学的明显变化表明，在室温和压力下，纳米管腔通过溶剂介导实现了功能化，这为设计纳米反应器以潜在控制纳米受限体积中的化学反应性提出了新策略。
