Mesoporous NiO nanoarchitectures (NAs) with controlled hexagonal platelet- and flower-like morphology were synthesized using facile hydrothermal methods in different reaction conditions. The NiO NAs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption /desorption isotherms, and wide-angle X-ray diffraction. It was found that controlled morphology, large surface areas, and high crystallinity of NiO NAs offered high catalytic reactivity toward Knoevenagel condensation reactions. Large reaction yields in an aqueous media and easy separation of the NiO NAs without losing the catalytic activity were observed. Further, the formation mechanism of bonds over NiO NAs surface was explored by density functional theory (DFT). These findings open a new avenue for efficient bonds formation using reusable NiO NAs catalyst without using any expensive solvents.

中文翻译：

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活性亚甲基和取代醛在介孔氧化镍纳米结构上的缩合：结合实验和 DFT 研究

使用简便的水热方法在不同反应条件下合成了具有可控六方片状和花状形态的介孔 NiO 纳米结构 (NAs)。NiO NAs 通过扫描电子显微镜 (SEM)、透射电子显微镜 (TEM)、N ₂吸附/解吸等温线和广角 X 射线衍射进行表征。研究发现，NiO NAs 的受控形态、大表面积和高结晶度为 Knoevenagel 缩合反应提供了高催化反应性。观察到在水性介质中反应产率大，并且在不损失催化活性的情况下容易分离 NiO NAs。此外，形成机制通过密度泛函理论（DFT）探索了 NiO NAs 表面上的键。这些发现为使用可重复使用的 NiO NAs 催化剂有效地形成键开辟了一条新途径，而无需使用任何昂贵的溶剂。