This work systematically investigated the crystallization process of NiAl‐layered double hydroxide (NiAl‐LDH) with a Ni(II)/Al(III) ratio of 3 under different crystallization conditions. The results showed that the prepared NiAl‐LDH first exhibits sheet‐like morphology, which transforms into a hexagonal platelet with further growth. The lateral size and thickness of the prepared NiAl‐LDH are ~10–284 nm and ~2–31 nm, respectively. Based on the evolution of morphology, particle size and crystallinity, the growth mechanism of NiAl‐LDH was first proposed. The growth of NiAl‐LDH in the lateral dimension was governed by Ostwald ripening, while the increase in c direction was dominated by oriented particle attachment before precipitation and dissolution equilibrium. Afterward, the growth of NiAl‐LDH was dominated by the oriented particle attachment, leading to further growth of NiAl‐LDH. Moreover, a rotating packed bed (RPB) was first adopted to crystallize NiAl‐LDH. The results show that RPB can greatly enhance the growth of NiAl‐LDH.

中文翻译：

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共沉淀法合成 Ni‐Al 层状双氢氧化物的生长机理和过程强化


本工作系统研究了不同结晶条件下 Ni（II）/Al（III） 比为 3 的 NiAl-层状双氢氧化物 （NiAl-LDH） 的结晶过程。结果表明，制备的 NiAl-LDH 首先呈现片状形态，随着进一步生长，它转变为六边形血小板。制备的 NiAl-LDH 的横向尺寸和厚度分别为 ~10-284 nm 和 ~2-31 nm。根据形态、粒径和结晶度的演变，首次提出了 NiAl-LDH 的生长机制。NiAl-LDH 在横向维度上的生长受 Ostwald 成熟控制，而 c 方向的增加由沉淀和溶解平衡前定向颗粒附着主导。之后，NiAl-LDH 的生长以取向颗粒附着为主，导致 NiAl-LDH 的进一步生长。此外，首次采用旋转填充床 （RPB） 来结晶 NiAl-LDH。结果表明，RPB 可以大大促进 NiAl-LDH 的生长。