Yamaguchi Tetsuo, Kim Hyoung-Jun, Park Hee Jung, Kim Taeho, Khalid Zubair, Park Jin Kuen, Oh Jae-Min
Department of Energy and Materials Engineering, Dongguk University, Seoul 04620, Republic of Korea.
Plasma Convergence R&BD Division, Cheorwon Plasma Research Institute, 1620, Hoguk-ro, Galmal-eup, Cherwon-gun 24047, Gangwon-do, Republic of Korea.
Nanomaterials (Basel). 2023 Aug 18;13(16):2363. doi: 10.3390/nano13162363.
The surface morphology of Mg-Al-layered double hydroxide (LDH) was successfully controlled by reconstruction during systematic phase transformation from calcined LDH, which is referred to as layered double oxide (LDO). The LDH reconstructed its original phase by the hydration of LDO with expanded basal spacing when reacted with water, including carbonate or methyl orange molecules. During the reaction, the degree of crystal growth along the ab-plane and stacking along the c-axis was significantly influenced by the molecular size and the reaction conditions. The lower concentration of carbonate gave smaller particles on the surface of larger LDO (2000 nm), while the higher concentration induced a sand-rose structure. The reconstruction of smaller-sized LDH (350 nm) did not depend on the concentration of carbonate due to effective adsorption, and it gave a sand-rose structure and exfoliated the LDH layers. The higher the concentration of methyl orange and the longer the reaction time applied, the rougher the surface was obtained with a certain threshold point of the methyl orange concentration. The surface roughness generally increased with the loading mount of methyl orange. However, the degree of the surface roughness even increased after the methyl orange loading reached equilibrium. The result suggested that the surface roughening was mediated by not only the incorporation of guest molecules into the LDH but also a crystal arrangement after a sufficient amount of methyl orange was accommodated.
通过从煅烧的层状双氢氧化物（LDH）（即层状双氧化物，LDO）进行系统的相变过程中的重构，成功控制了镁铝层状双氢氧化物（LDH）的表面形态。当与水（包括碳酸盐或甲基橙分子）反应时，LDH通过LDO的水合作用以及基底间距的扩大来重构其原始相。在反应过程中，沿ab平面的晶体生长程度和沿c轴的堆积程度受到分子大小和反应条件的显著影响。较低浓度的碳酸盐在较大尺寸的LDO（2000 nm）表面产生较小的颗粒，而较高浓度则诱导形成砂玫瑰结构。由于有效吸附，较小尺寸（350 nm）的LDH的重构不依赖于碳酸盐浓度，并且产生砂玫瑰结构并使LDH层剥离。甲基橙浓度越高且反应时间越长，在甲基橙浓度达到一定阈值时表面越粗糙。表面粗糙度通常随着甲基橙负载量的增加而增加。然而，在甲基橙负载达到平衡后，表面粗糙度程度甚至还会增加。结果表明，表面粗糙化不仅是由客体分子掺入LDH介导的，而且在容纳足够量的甲基橙后还由晶体排列介导。
