Adsorption, dissociation and diffusion behavior of H 2 O on the PuO 2 (111) surface from DFT + U -D3: the role of hydrogen bonding

The interaction between H O and plutonium oxide is an essential aspect of researching plutonium corrosion. We systematically studied the adsorption, dissociation, and diffusion of H O molecules on the PuO (111) surface with the DFT + -D3 scheme. We find that the top of the Pu atom is the most stable adsorption site for H O molecules on the PuO (111) surface. When multiple H O molecules are adsorbed, hydrogen bonding between molecules can increase the average adsorption energy. H O molecules will dissociate into H atoms and O-H groups under certain conditions. We have paid special attention to the role of hydrogen bonds between H O molecules. When the coverage of H O molecules is low, hydrogen bonds can significantly promote the adsorption and dissociation of H O molecules. And H O tends to exist on the surface of plutonium oxide in dissociated and molecular mixed states. The H atoms produced by the dissociation of H O molecules are not easily diffused, which may be related to the hydrogen bonding between O-H groups. This work has important theoretical significance for deepening the understanding of the corrosion mechanism of plutonium.