2026年“核理安邦”联合博士生学术论坛

UO₂(111) 表面高覆盖度下水分子吸附与解离的密度泛函理论研究

Not scheduled

12m

地址：清华大学校内

口头报告 环、化、材、技、能源战略 环、化、材、技、能源战略

Speaker

松林 朱 (成都理工大学核技术与自动化工程学院)

Abstract

This study examines the behavior of water molecules on the UO2(111) surface, focusing on adsorption and dissociation, using density functional theory (DFT+U). We determined the adsorption configuration of a single water molecule and observed that it exhibits a tendency toward dissociative adsorption, characterized by a low energy barrier for dissociation.In the case of multiple water molecules, the presence of additional water molecules promotes dissociation, and the hydrogen bond interactions between water molecules gradually strengthen. Water molecules that act as hydrogen bond donors interact more strongly with the UO₂(111) surface. Furthermore, in the mixed adsorption on the UO₂(111) surface, the system's stability is significantly influenced by hydrogen bonds. Based on the analysis of dissociation energy barriers and adsorption energies, the surface adsorption shows a clear preference when the ratio of molecular water to dissociated water is 1:1. At a 1 ML coverage, as the water molecules fully dissociate, the repulsive interactions between the surface adsorbates significantly increase, leading to a decrease in the dissociative adsorption energy to -0.32 eV. In the thermodynamic calculations, 0.5 ML coverage is the optimal configuration, and as the temperature increases, water molecules gradually desorb, eventually leading to a clean surface.

摘要

本研究采用密度泛函理论（DFT+U），研究了水分子在UO₂(111) 表面的行为，重点关注其吸附与解离过程。我们确定了单个水分子的吸附构型，发现其表现出解离吸附趋势，具有较低的解离能垒。在多水分子体系中，额外水分子的存在会促进解离，且水分子间的氢键作用逐渐增强。作为氢键供体的水分子与 UO₂(111) 表面的相互作用更强。此外，在 UO₂(111) 表面的混合吸附中，氢键对体系稳定性具有显著影响。通过解离能垒与吸附能分析表明，当分子水与解离水比例为1:1时，表面吸附具有明显优势。在1 ML 覆盖度下，随着水分子完全解离，表面吸附物间的排斥作用显著增强，导致解离吸附能降至 -0.32 eV。热力学计算表明，0.5 ML 覆盖度为最优构型；随着温度升高，水分子逐渐脱附，最终形成清洁表面。

Presentation materials

UO2_H2O_朱松林_成都理工大学.pptx