Revisiting the Hydrogen Evolution Kinetics of Magnesium Corrosion: a First-principles Study with Constant Potential Method

Due to the lightweight properties and natural abundance, magnesium alloys have attracted wide research interests, while its practical applications are still hindered by the inherent susceptibility to galvanic corrosion. In this work, density functional theory (DFT) calculations along with the constant potential method have been employed to study the corrosion polarization curve for Mg alloys. Through first-principles simulations of pure Mg(0001) surfaces, the hydrogen evolution reaction kinetics and corrosion polarization curves have been determined in an ab initio way, from which the corrosion current density, corrosion potential, and Tafel slopes obtained are in consistence with experimental resutls. The Brønsted-Evans-Polanyi (BEP) relationship between the hydrogen adsorption energy and the activation energy of Volmer or Heyrovsky reactions has been further established to accelerate the corrosion kinetics determination for Mg alloy. This computational framework not only deciphers the feasibility to accurately predict the metal alloy’s hydrogen evolution corrosion kinetics from atomistic simulations, but also paves the way to further accelerate the development of corrosion-resistant metal alloys through rational screening based on hydrogen adsorption energy.