Hydrogenation kinetics on the α-U (001) surface: Nb doping and DFT + U-D3

Hydrogenation corrosion significantly limits the performance of metallic U as a nuclear material. Investigating its hydrogen corrosion mechanism is crucial for ensuring the safe and efficient operation of nuclear energy systems. First-principles DFT + U and AIMD simulations were employed to study the adsorption mechanisms of H 2 on both pure and Nb-doped α-U (001) surfaces, with detailed analysis of the electronic structure. The results indicate that Nb doping significantly alters the H 2 adsorption and dissociation behavior by inducing surface charge redistribution and electronic structure reconstruction. During the molecular adsorption stage, the electron modulation and lattice strain caused by doping synergistically reduce the adsorption energy. After dissociation, the enhanced charge transfer promotes stable atomic adsorption, with hydrogen traps forming at the Nb surrounding. DOS and COHP analysis indicate that there is stronger orbital hybridization and bond interaction between U–H, which, in collaboration with Nb traps, anchors H atoms on the surface, forming a uniform and high-energy barrier capture region, thereby effectively inhibiting further hydrogen diffusion. This study delved deeply into the correlation mechanism of composition - electronic state - reactivity at the electronic structure level, providing a theoretical basis for the rational design of anti-corrosion surfaces. • Surface electronic reconstruction and strain co-regulate hydrogen adsorption behavior. • H-traps around Nb and strong U–H interactions jointly enhance H anchoring to suppress surface hydriding. • Enhanced H-metal bonding is the key electronic mechanism for inhibiting hydrogen damage.