Wang Wenhui, Chee See Wee, Yan Hongwei, Erofeev Ivan, Mirsaidov Utkur
Department of Physics, National University of Singapore, Singapore 117551, Singapore.
Centre for BioImaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore 117557, Singapore.
Nano Lett. 2021 Jul 28;21(14):5977-5983. doi: 10.1021/acs.nanolett.1c00898. Epub 2021 Jul 13.
Layered double hydroxides (LDHs) are a class of lamellar materials with a wide range of potential catalytic applications. LDHs form from positively charged 2D atomic layers separated by charge-balancing anions and solvent molecules. Typically, nanoscale LDH sheets can grow vertical or parallel to a substrate, exposing their different active facets. These two growth modes of LDH nanosheets have a significant impact on their electrocatalytic properties, yet the details of their growth remain unknown, hindering our ability to design and synthesize high-performance LDH-based electrocatalysts. Here, we investigate the growth pathways of LDH nanosheets using electrochemical liquid-phase transmission electron microscopy (TEM) and show that the growth modes of LDH nanosheets can be controlled by tuning the precursor concentrations. Moreover, our observations reveal that LDH nanosheets grow via two pathways: (1) monomer addition, where the adatoms are heterogeneously deposited onto the LDH nanosheets, and (2) coalescence, where adjacent nanosheets merge together.
层状双氢氧化物(LDHs)是一类具有广泛潜在催化应用的层状材料。LDHs由带正电荷的二维原子层构成,这些原子层被电荷平衡阴离子和溶剂分子分隔开。通常,纳米级LDH片可以垂直于或平行于基底生长,暴露出它们不同的活性面。LDH纳米片的这两种生长模式对其电催化性能有重大影响,然而其生长细节仍不为人知,这阻碍了我们设计和合成高性能LDH基电催化剂的能力。在此,我们使用电化学液相透射电子显微镜(TEM)研究了LDH纳米片的生长途径,并表明可以通过调节前驱体浓度来控制LDH纳米片的生长模式。此外,我们的观察结果表明,LDH纳米片通过两种途径生长:(1)单体添加,即吸附原子非均匀地沉积在LDH纳米片上;(2)聚结,即相邻纳米片合并在一起。