德国马普学会钢铁研究所Baptiste Gault团队报道了胶体纳米材料中的碱污染，开启晶界杂质工程。相关研究成果于2022年1月4日发表于国际顶尖学术期刊《美国化学会杂志》。

金属纳米凝胶结合了大表面积、高的结构稳定性和对各种化学反应的高催化活性。其性能是由成分的原子级分布决定的，但分析它们的亚纳米级结构和成分以指导性能优化仍然极具挑战性。

该文中，研究人员使用传统的湿化学方法合成了钯纳米凝胶，近原子级分析表明，来自反应物（Na和K）的杂质整合到多晶凝胶的晶界中，通常是具有高催化活性的位点。研究人员证明了杂质的含量受反应条件的控制。基于从头算计算，研究人员提供了一个详细的机制来解释表面结合杂质是如何被困在合成过程中粒子聚结形成的晶界上的，这可能会促进它们的脱粘。如果控制杂质集成到晶界可能为设计新的纳米凝胶提供机会。

附：英文原文

Title: Understanding Alkali Contamination in Colloidal Nanomaterials to Unlock Grain Boundary Impurity Engineering

Author: Se-Ho Kim, Su-Hyun Yoo, Poulami Chakraborty, Jiwon Jeong, Joohyun Lim, Ayman A. El-Zoka, Xuyang Zhou, Leigh T. Stephenson, Tilmann Hickel, Jrg Neugebauer, Christina Scheu, Mira Todorova, Baptiste Gault

Issue&Volume: January 4, 2022

Abstract: Metal nanogels combine a large surface area, a high structural stability, and a high catalytic activity toward a variety of chemical reactions. Their performance is underpinned by the atomic-level distribution of their constituents, yet analyzing their subnanoscale structure and composition to guide property optimization remains extremely challenging. Here, we synthesized Pd nanogels using a conventional wet chemistry route, and a near-atomic-scale analysis reveals that impurities from the reactants (Na and K) are integrated into the grain boundaries of the poly crystalline gel, typically loci of high catalytic activity. We demonstrate that the level of impurities is controlled by the reaction condition. Based on ab initio calculations, we provide a detailed mechanism to explain how surface-bound impurities become trapped at grain boundaries that form as the particles coalesce during synthesis, possibly facilitating their decohesion. If controlled, impurity integration into grain boundaries may offer opportunities for designing new nanogels.

DOI: 10.1021/jacs.1c11680

Source: https://pubs.acs.org/doi/10.1021/jacs.1c11680