Greatly Boosting Seawater Hydrogen Evolution by Surface Amorphization and Morphology Engineering on MoO 2 /Ni 3 (PO 4 ) 2

Abstract Hydrogen production through seawater electrolysis faces several challenges, one of which involves the development of electrocatalysts with high catalytic performance. Here, surface amorphization and morphology engineering are combined to design a novel electrocatalyst for highly‐efficient hydrogen evolution reaction (HER). The surface‐amorphized MoO 2 /Ni 3 (PO 4 ) 2 microcolumns supported on nickel foam (SA‐MoO 2 /Ni 3 (PO 4 ) 2 /NF) display remarkable performance with low overpotentials of 34 and 46 mV at a current density of 10 mA cm −2 in 1 m KOH and alkaline seawater, respectively. In addition, the alkaline electrolysis cell (AEC) integrated with SA‐MoO 2 /Ni 3 (PO 4 ) 2 /NF as the cathode and Ni foam as the anode achieves a current density of 100 mA cm −2 at 1.87 V in 6 m KOH seawater at 60 °C, superior to that of industrial NiMo electrode as cathode (2.05 V). DFT calculations demonstrate that the surface amorphous layer (MoO x ) improves the hydrogen adsorption energy of sample and reduces the energy barrier of water dissociation. It is found that substantial improvement in catalytic performance stems from the synergistic effect between surface amorphization and unique microcolumn morphology. These findings may provide insights into combining surface amorphization and morphology engineering strategies to enhance catalytic performance and pave the way for the development of highly efficient seawater HER electrocatalysts.