Dipole Coupling Accelerated H 2 O Dissociation by Magnesium-Based Intermetallic Catalysts.

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.