Hydrogen Spillover Mechanism of Superaerophobic NiSe2‐Ni5P4 Electrocatalyst to Promote Hydrogen Evolution in Saline Water

Abstract

AbstractThe hydrogen spillover mechanism of metal‐supported electrocatalyst can significantly improve HER activity. However, the rational design of binary heterojunction hydrogen spillover electrocatalysts remains a challenge. Here, a NiSe2‐Ni5P4 heterojunction electrocatalyst with superaerophobic structure is synthesized by using a simple substrate self‐derived strategy. Experimental characterization and theoretical calculation reveal the hydrogen spillover mechanism of NiSe2‐Ni5P4 heterogeneous electrocatalyst. NiSe2 and Ni5P4 synergistically promote the adsorption/dissociation of H2O and the adsorption of H*, respectively. The smaller ΔΦ effectively reduced the electron density at the interface, weakening the proton adsorption at the interface and promoting the migration of H* from NiSe2 to Ni5P4. The NiSe2‐Ni5P4 exhibits excellent HER activity in alkaline electrolyte, requiring only a potential of 65, 270 mV to achieve a current density of 10, 500 mA cm−2, respectively, and a stability of up to 200 h. Moreover, the design of NiSe2‐Ni5P4 with superaerophobic structure can reduce the deposition of impurity ions on the electrode surface and avoid Cl− corrosion of the electrode, which results in NiSe2‐Ni5P4 showing better HER activity and stability than commercial Pt/C in brackish water. This study deepens the understanding of hydrogen spillover mechanism of binary heterojunction electrocatalysts, broadens the application of hydrogen production in complex water quality.