Two-Dimensional Nanomaterials as Anticorrosion Surface Coatings for Uranium Metal: Physical Insights from First-Principles Theory

Corrosion protection is vital to ensure the reliability and long-term durability of metal components. Coating surfaces with two-dimensional (2D) materials is an attractive approach due to the strength, impermeability, and chemical inertness of many materials in this family. The selection of the best 2D coating relies on a detailed understanding of the interaction between 2D nanomaterials and the metal. In this paper, we report the first theoretical study on the interfacial properties of the 2D nanomaterial and metal uranium (U) using first-principles calculations. We concentrated on the study of protecting U metal surfaces because this material is very susceptible to surface corrosion, and it is of tremendous technological importance to the nuclear industry. The corrosion of U is a great challenge for its safe handling, usage, and storage. Six representative 2D nanomaterials, including graphene, h-BN, MoS2, MoSe2, and oxygen passivated Ti2C layer (Ti2CO2 and Ti2CO), were selected from the 2D material library. Our calculations show that the binding energies of graphene and h-BN are smaller than -1.0 J/m(2) on U surfaces. The binding energies of MoS2 and MoSe2 are in the range from -1.5 to -2.0 J/m(2). Ti2C-based MXenes (Ti2CO2 and Ti2CO) have binding energies larger than -2.0 J/m(2). The binding strength is traced back to the charge transfer at the interface which also leads to the quenching of surface magnetic moments. It is found that the binding strength is not sensitive to the phase and surface orientation of U metal. Among all the studied 2D nanomaterials, Ti2C-based MXenes are the most suitable coatings for U. These physical insights into the interfacial properties can provide guidance to the selection of chemically inert and thermodynamically stable 2D anticorrosion coatings that can strongly bind to the surfaces of U and other materials.