The approaching Zn+2 ion first bind

接近的Zn + 2离子首先与桥接羟基键合（图3）。由于表面羟基与Zn + 2离子周围的第一水合壳物种之间存在氢键相互作用，因此很容易发生此过程。我们通过应用键约束方法（支持信息，图S1）研究了这种结合过程的能量障碍。当Zn + 2接近表面时，Zn + 2脱离水合壳本身并与桥连羟基结合所需的能量经计算为3 kcal / mol。吸附能非常小，因为由于氧孤对与二价Zn + 2离子空轨道之间的相互作用，Zn + 2可以直接与桥连羟基的氧结合；因此，没有用于吸附的配体交换过程。从而，表面的羟基化不会像通常预期的那样降低晶粒的生长。相反，它非常有助于初始吸附，从而防止重结晶限制CSP中的晶粒生长。但是，在系统中存在过量的HAc（4.6m和9m）的情况下，观察到的结果有所不同。在模拟中，HAc分子在ZnO表面解离并结合到带正电荷的表面部位，过量时，乙酸盐分子覆盖表面的很大一部分并倾向于留在表面上。因此，这种强吸附使得Zn + 2离子和乙酸盐之间的交换更加困难，并延迟了重结晶直至达到高温。在2m酸浓度下可在模拟中建模的HAc分子数量有限；因此，为了检查0m和2m HAc条件之间的差异，我们针对这两种特定情况扩展了仿真大小（图2D）。从图中可以看出，没有重大意义<br>在结晶中观察到差异，因为大多数HAc分子与溶液中的Zn + 2离子结合，并且不像4.6m和9m情况那样覆盖表面。

The approaching Zn+2 ion first binds to the bridging hydroxyl (Figure 3). This process is observed to occur easily due to the hydrogen-bonding interactions between the surface hydroxyls and the first hydration shell species around the Zn+2 ion. We investigated the energy barriers of this binding process by applying a bond-restraint approach (Supporting Information, Figure S1). When Zn+2 approaches the surface, the required energy for Zn+2 to divest itself of the hydration shell and bind to the bridging hydroxyl was calculated as 3 kcal/mol. The adsorption energy is very small because Zn+2 can directly bind to the oxygen of the bridging hydroxyl due to the interaction between oxygen lone pairs and divalent Zn+2 ion empty orbitals; therefore, there is no ligand exchange process for adsorption. Thus, hydroxylation of the surface does not reduce grain growth as typically expected. Instead, it very much aids the initial adsorption, which prevents recrystallization from limiting grain growth in CSP. However, it is observed to be different in the presence of an excess amount of HAc (4.6m and 9m) in the system. In the simulations, HAc molecules dissociate on the ZnO surface and bind to the positively charged surface sites, and when in excess, acetate molecules cover a significant part of the surface and tend to stay on the surface. Thus, this strong adsorption makes the exchange between the Zn+2 ions and acetate more difficult and delays recrystallization until elevated temperatures are reached. The number of HAc molecules that could be modeled in the simulation with 2m acid concentration was limited; therefore, in order to examine the difference between 0m and 2m HAc conditions, we extended our simulation sizes for these two specific cases (Figure 2D). As can be seen from the figure, no significant<br>difference is observed in crystallization, because most of the HAc molecules bind to Zn+2 ions in the solution and do not cover the surface as happened in the 4.6m and 9m cases.

接近的锌离子首先与桥连羟基结合（图3）。这一过程很容易发生，因为锌离子周围的表面羟基和第一水合壳层物种之间的氢键相互作用。我们应用键约束方法（支持信息，图S1）研究了这种结合过程的能量屏障。当Zn+2接近表面时，Zn+2从水化壳中剥离并与桥羟基结合所需的能量为3kcal/mol，由于氧孤对与二价Zn+2离子空位相互作用，Zn+2能直接与桥羟基的氧结合，吸附能很小轨道；因此，没有配体交换过程用于吸附。因此，表面羟基化并不像通常预期的那样减少晶粒生长。相反，它非常有助于初始吸附，防止重结晶限制CSP晶粒生长。然而，当系统中存在过量的HAc（460万和9m）时，情况就不同了。在模拟中，HAc分子在氧化锌表面解离并与带正电的表面结合，当过量时，醋酸盐分子覆盖了表面的很大一部分并倾向于停留在表面。因此，这种强烈的吸附使Zn+2离子和乙酸盐之间的交换更加困难，并且延迟再结晶直到达到高温。在酸浓度为2 m的模拟中，可以模拟的HAc分子数量有限；因此，为了检验0 m和2 m HAc条件之间的差异，我们将模拟尺寸扩展到这两种特定情况（图2D）。从图中可以看出<br>在结晶过程中观察到差异，因为大多数HAc分子与溶液中的Zn+2离子结合，不像在4.6m和9m的情况下那样覆盖表面。<br>