Hydrogen adsorption on Au (111), U (110), and nAu/U (110) alloy surfaces: A first-principles study

Hydrogen corrosion caused by uranium hydrogenation is a critical issue in nuclear materials that needs to be promptly addressed. Hydrogen adsorption is the primary link to the hydrogenation reaction. Herein, the stable H adsorption sites, adsorption energies and electronic density of states of U (110), Au (111), and nAu/U (110) alloy surfaces, respectively, are studied using the first-principles calculations. The H adsorption energy on the U (110) surface is high, while that of Au (111) is low. The most stable adsorption sites for the U (110) and Au (111) surfaces are hollow and fcc sites, respectively. The reason for U (110) surface's greater propensity to adsorb H than Au (111) is investigated. H preferentially adsorbs on the nAu/U (110) alloy surface at the hollow sites surrounded by more U atoms. All adsorption energies are lower than those of H on the pure U (110) surface, and decrease as the number of Au atoms n increases. The Au or Au–U alloy can be used for hydrogen barrier adsorption coatings on U surfaces, which will reduce H adsorption on the U surfaces from the source and will promote the improvement of the long-term H corrosion resistance of U materials.