Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Key Laboratory of Computational Physical Science (Ministry of Education), Fudan University, Shanghai 200433, China.
Phys Chem Chem Phys. 2013 Nov 14;15(42):18555-61. doi: 10.1039/c3cp53758g.
The electrocatalytic oxygen reduction reaction (ORR) on nanoparticles has attracted much attention in recent years for its significance in fuel cell applications. Here by combining density functional theory (DFT) calculations with the periodic continuum solvation model based on modified-Poisson-Boltzmann (CM-MPB) electrostatics, we analyzed the ORR activity on a set of differently sized Pt nanoparticles in order to identify the optimum particles for a better designed catalyst. We show that Pt nanoparticles of ∼2 nm size have the highest ORR mass activity, which is attributed to the variation of the effective reaction sites on the exposed {111} facet at the electrochemical conditions. We propose a type of a new nanocatalyst for the electrocatalytic oxygen reduction based on the knowledge from large-scale first principles simulations on Pt nanoparticles. The new catalyst has inert metal Au as the frame for the Pt nanoparticle and exposed Pt{111} sites are the active site for oxygen reduction. Such an architecture can not only prevent the initial O corrosion at the edge sites but also significantly improve the activity. The theoretical work provides a promising new direction for the rational design of a stable and active ORR catalyst via nano-structure engineering.
近年来，纳米颗粒上的电催化氧气还原反应（ORR）因其在燃料电池应用中的重要性而引起了广泛关注。在这里，我们通过结合密度泛函理论（DFT）计算和基于修正泊松-玻尔兹曼（CM-MPB）静电的周期性连续溶剂化模型，分析了一系列不同尺寸的 Pt 纳米颗粒上的 ORR 活性，以确定用于更好设计催化剂的最佳颗粒。我们表明，∼2nm 尺寸的 Pt 纳米颗粒具有最高的 ORR 质量活性，这归因于电化学条件下暴露的{111}面有效反应位点的变化。我们基于对 Pt 纳米颗粒的大规模第一性原理模拟的知识，提出了一种新型纳米催化剂用于电催化氧气还原。新型催化剂具有惰性金属 Au 作为 Pt 纳米颗粒的框架，暴露的 Pt{111}位点是氧气还原的活性位点。这种结构不仅可以防止边缘位点的初始 O 腐蚀，而且还可以显著提高活性。该理论工作为通过纳米结构工程合理设计稳定和活性的 ORR 催化剂提供了一个有前途的新方向。
