Institute of Chemical Research of Catalonia, ICIQ, The Barcelona Institute of Science and Technology, Av. Països Catalans, 16, 43007, Tarragona, Spain.
Nanoscale. 2017 Sep 14;9(35):13089-13094. doi: 10.1039/c7nr03889e.
The shape control of nanoparticles constitutes one of the main challenges in today's nanotechnology. The synthetic procedures are based on trial-and-error methods and are difficult to rationalize as many ingredients are typically used. For instance, concave nanoparticles exhibiting high-index facets can be obtained from Pt with different HCl treatments. These structures present exceptional capacities when are employed as catalysts in electrochemical processes, as they maximize the activity per mass unit of the expensive material. Here we show how atomistic simulations based on density functional theory that take into account the environment can predict the morphology for the nanostructures and how it is even possible to address the appearance of concave structures. To describe the control by etching, we have reformulated the Wulff construction through the use of a geometric model that leads to concave polyhedra, which have a larger surface-to-volume ratio compared to that for nanocubes. Such an increase makes these sorts of nanoparticles excellent candidates to improve electrocatalytic performance.
纳米粒子的形状控制是当今纳米技术的主要挑战之一。合成过程基于反复试验的方法，并且由于通常使用多种成分，因此难以合理化。例如，通过对 Pt 进行不同的 HCl 处理，可以获得具有高指数晶面的凹面纳米粒子。这些结构在用作电化学过程中的催化剂时具有非凡的能力，因为它们使昂贵材料的单位质量的活性最大化。在这里，我们展示了如何基于考虑环境的密度泛函理论的原子模拟来预测纳米结构的形态，以及如何解决凹面结构的出现问题。为了描述通过蚀刻进行的控制，我们通过使用一个几何模型对 Wulff 构造进行了重新表述，该模型导致了具有更大表面积与体积比的凹多面体，与纳米立方体相比。这种增加使得这些类型的纳米粒子成为提高电催化性能的优秀候选者。
