Adsorption and diffusion of actinyls on the basal gibbsite (001) surface: a theoretical perspective

Xingyu Xie; Mingyang Shi; Xuying Zhou; Xianqiong Li; Gang Jiang; Jiguang Du

doi:10.1039/d3cp04088g

Adsorption and diffusion of actinyls on the basal gibbsite (001) surface: a theoretical perspective

Phys Chem Chem Phys. 2023 Nov 8;25(43):29680-29689. doi: 10.1039/d3cp04088g.

Authors

Xingyu Xie^{1

2}, Mingyang Shi¹, Xuying Zhou², Xianqiong Li², Gang Jiang², Jiguang Du¹

Affiliations

¹ College of Physics, Sichuan University, Chengdu 610064, China. dujg@scu.edu.cn.
² Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China.

PMID: 37882627
DOI: 10.1039/d3cp04088g

Abstract

Actinides are an important component of nuclear fuel for nuclear power and affect human health, and a key process in the transport of radionuclides in the environment is adsorption on mineral surfaces. In this work, we have used density functional theory (DFT) to investigate the microscopic adsorption and diffusion mechanisms of actinyls, U(V), U(VI), Np(V), Np(VI) Pu(V), and Pu(VI), on the gibbsite (001) surface. Actinyls(VI) are attached to the gibbsite surface through two An-O_s bonds, which results in a bidentate inner sphere mode, while actinyls(V) favor a monodentate inner sphere adsorption mode with the gibbsite (001) surface. The solvent effects were considered through an explicit water cluster model. All the actinyls studied can be efficiently adsorbed on the gibbsite (001) surface with binding energies ranging from -113.9 kJ mol^-1 to -341.2 kJ mol^-1. Electronic structure analyses indicate that the cooperation of the An-O_s bonds and hydrogen bonds leads to high adsorption stability of the actinyls with the gibbsite surface. The diffusion barriers of the actinyls on the gibbsite surface were determined, and the high energy barriers indicate that this type of gas-phase diffusion process is not likely to take place.