Interfacial Chemical Bond Modulation of Co₃(PO₄)₂-MoO_3–<i>x</i> Heterostructures for Alkaline Water/Seawater Splitting

Abstract

The development of a high current density with high energy conversion efficiency electrocatalyst is vital for large-scale industrial application of alkaline water splitting, particularly seawater splitting. Herein, we design a self-supporting Co₃(PO₄)₂-MoO_3-<i>x</i>/CoMoO₄/NF superaerophobic electrode with a three-dimensional structure for high-performance hydrogen evolution reaction (HER) by a reasonable devise of possible "Co-O-Mo hybridization" on the interface. The "Co-O-Mo hybridization" interfaces induce charge transfer and generation of fresh oxygen vacancy active sites. Consequently, the unique heterostructures greatly facilitate the dissociation process of H₂O molecules and enable efficient hydrogen spillover, leading to excellent HER performance with ultralow overpotentials (76 and 130 mV at 100 and 500 mA cm^-2) and long-term durability of 100 h in an alkaline electrolyte. Theoretical calculations reveal that the Co₃(PO₄)₂-MoO_3-<i>x</i>/CoMoO₄/NF promotes the adsorption/dissociation process of H₂O molecules to play a crucial role in improving the stability and activity of HER. Our results exhibit that the HER activity of non-noble metal electrocatalysts can be greatly enhanced by rational interfacial chemical bonding to modulate the heterostructures.