Ab initio molecular dynamics (AIMD) simulations of the interlayer contents of LDH-Gluconate

Initially, three different arrangements of the gluconate anion in the LDH interlayer were selected (Figure 1), namely, i) tilted in relation to the cationic layer and antiparallel to each other (tilted antiparallel), ii) tilted in relation to the cationic layer and parallel to each other (tilted parallel), and iii) planar in relation to the cationic layer and antiparallel to each other (planar antiparallel).

After building the initial supercells, Born−Oppenheimer AIMD simulations were performed at constant temperature (300 K), fixing the positions of aluminum and zinc atoms, and maintaining the supercell vectors also constant. The time step was 1.2 fs and the total time of simulation was 12 ps, which were chosen according to the procedure adopted by other authors to study the same type of materials12. The temperature was controlled using the Berendsen barostat.

The most energetically favorable structure from the MD results, together with structures obtained at specific time frames (0, 3, 6, 9 and 12 ps) were chosen for total geometry optimization, allowing the positions of all atoms and the cell vectors to relax.

最初，针对LDH层间葡萄糖酸根离子的三种不同排列方式被选定为研究对象（见图1），分别为：i) 相对于阳离子层倾斜且相互之间为反平行排列（倾斜反平行），ii) 相对于阳离子层倾斜且相互之间为平行排列（倾斜平行），以及iii) 相对于阳离子层为平面排列且相互之间为反平行排列（平面反平行）。在构建初始的超胞之后，进行了Born−Oppenheimer分子动力学模拟，模拟条件为恒温（300 K），固定铝和锌原子的位置，并保持超胞矢量的恒定。时间步长为1.2 fs，总模拟时间为12 ps，这些参数的选择参照了其他研究者针对同类材料所采用的程序12。温度控制采用Berendsen压阻器。从分子动力学结果中选取了能量最有利于的结构，以及特定时间点（0、3、6、9和12 ps）获得的结构，用于进行全面的几何优化，允许所有原子的位置和细胞矢量进行松弛。