复旦大学刘韡韬研究团队原位和频光谱揭示了水中氧化物表面的非常规结构演化。相关研究成果于2024年10月14日发表在国际知名学术期刊《自然—化学》。

在自然界和现代工业应用中，氧化物-水界面承载着的重要反应。然而，由于难以接近埋藏的氧化物表面，在分子水平上仍然缺乏对这些界面的准确了解。

该文中，研究人员报告了一种能够实现液态水中氧化物表面的原位和频振动光谱的实验方案。在二氧化硅-水界面上的应用揭示了与水发生意想不到的表面反应途径。

通过从头计算分子动力学和元动力学模拟，发现了一种由表面羟基化基团脱质子化引发的表面重建，从而产生了非常规的五配位硅物种。这些结果有助于揭开几十年前发现的二氧化硅水溶液的多峰化学的神秘面纱，带来了改变当前理解的新信息。

该研究将为未来其他氧化物-水界面的深入物理和化学表征提供新的机会。

附：英文原文

Title: Unconventional structural evolution of an oxide surface in water unveiled by in situ sum-frequency spectroscopy

Author: Li, Xiaoqun, Brigiano, Flavio S., Pezzotti, Simone, Liu, Xinyi, Chen, Wanlin, Chen, Huiling, Li, Ying, Li, Hui, Lin, Xin, Zheng, Wenqi, Wang, Yuchong, Shen, Yue Ron, Gaigeot, Marie-Pierre, Liu, Wei-Tao

Issue&Volume: 2024-10-14

Abstract: Oxide–water interfaces host a wide range of important reactions in nature and modern industrial applications; however, accurate knowledge about these interfaces is still lacking at the molecular level owing to difficulties in accessing buried oxide surfaces. Here we report an experimental scheme enabling in situ sum-frequency vibrational spectroscopy of oxide surfaces in liquid water. Application to the silica–water interface revealed the emergence of unexpected surface reaction pathways with water. With ab initio molecular dynamics and metadynamics simulations, we uncovered a surface reconstruction, triggered by deprotonation of surface hydroxylated groups, that led to unconventional five-coordinated silicon species. The results help demystify the multimodal chemistry of aqueous silica discovered decades ago, bringing in fresh information that modifies the current understanding. Our study will provide new opportunities for future in-depth physical and chemical characterizations of other oxide–water interfaces.

DOI: 10.1038/s41557-024-01658-y

Source: https://www.nature.com/articles/s41557-024-01658-y