Geng Xin, Vega-Paredes Miquel, Wang Zhenyu, Ophus Colin, Lu Pengfei, Ma Yan, Zhang Siyuan, Scheu Christina, Liebscher Christian H, Gault Baptiste
Max Planck Institute for Sustainable Materials, Düsseldorf, Germany.
National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
Nat Commun. 2024 Oct 2;15(1):8534. doi: 10.1038/s41467-024-52919-w.
Grain boundaries in noble metal catalysts have been identified as critical sites for enhancing catalytic activity in electrochemical reactions such as the oxygen reduction reaction. However, conventional methods to modify grain boundary density often alter particle size, shape, and morphology, obscuring the specific role of grain boundaries in catalytic performance. This study addresses these challenges by employing gold nanoparticle assemblies to control grain boundary density through the manipulation of nanoparticle collision frequency during synthesis. We demonstrate a direct correlation between increased grain boundary density and enhanced two-electron oxygen reduction reaction activity, achieving a significant improvement in both specific and mass activity. Additionally, the gold nanoparticle assemblies with high grain boundary density exhibit remarkable electrochemical stability, attributed to boron segregation at the grain boundaries, which prevents structural degradation. This work provides a promising strategy for optimizing the activity, selectivity, and stability of noble metal catalysts through precise grain boundary engineering.
贵金属催化剂中的晶界已被确定为增强电化学反应（如氧还原反应）催化活性的关键位点。然而，传统的改变晶界密度的方法通常会改变颗粒大小、形状和形态，从而模糊了晶界在催化性能中的具体作用。本研究通过使用金纳米颗粒组装体来控制晶界密度，即在合成过程中通过操纵纳米颗粒的碰撞频率来解决这些挑战。我们证明了晶界密度的增加与两电子氧还原反应活性的增强之间存在直接关联，在比活性和质量活性方面都取得了显著提高。此外，具有高晶界密度的金纳米颗粒组装体表现出卓越的电化学稳定性，这归因于硼在晶界处的偏析，从而防止了结构降解。这项工作为通过精确的晶界工程优化贵金属催化剂的活性、选择性和稳定性提供了一种有前景的策略。
