Dipole Coupling Accelerated H2O Dissociation by Magnesium‐Based Intermetallic Catalysts

Abstract The water (H 2 O) dissociation is critical for various H 2 O‐associated reactions, including water gas shift, hydrogen evolution reaction and hydrolysis corrosion. While the d ‐band center concept offers a catalyst design guideline for H 2 O activation, it cannot be applied to intermetallic or main group elements‐based systems because Coulomb interaction was not considered. Herein, using hydrolysis corrosion of Mg as an example, we illustrate the critical role of the dipole of the intermetallic catalysts for H 2 O dissociation. The H 2 O dissociation kinetics can be enhanced using Mg x Me y ( Me =Co, Ni, Cu, Si and Al) as catalysts, and the hydrogen generation rate of Mg 2 Ni‐loaded Mg reached 80 times as high as Ni‐loaded Mg. The adsorbed H 2 O molecules strongly couple with the Mg− Me dipole of Mg x Me y , lowering the H 2 O dissociation barrier. The dipole‐based H 2 O dissociation mechanism is applicable to non‐transition metal‐based systems, such as Mg 2 Si and Mg 17 Al 12 , offering a flexible catalyst design strategy for controllable H 2 O dissociation.