Nanosized NiFeSe2/NiCo2O4 hierarchical arrays on Ni foam as an advanced electrocatalyst for hydrogen generation

Abstract

The rational design of composite catalysts is critically essential for electrochemical water splitting. Here, we report on a novel hierarchical composite that comprises NiFeSe₂ nanoparticles and NiCo₂O₄ nanoflakes supported on nickel foam (NF) as an efficient electrocatalyst for the hydrogen evolution reaction (HER). The conjunction of the NiFeSe₂ nanoparticles and NiCo₂O₄ nanoflakes introduces a new synergistic effect for the HER, resulting in an improved NiCo₂O₄ catalyst. The as-prepared NiFeSe₂/NiCo₂O₄/NF electrode exhibited an enhanced HER activity, with a low overpotential of 83 mV at a current density of 10 mA cm⁻², a low Tafel slope of 45 mV dec⁻¹, and an excellent long-term electrochemical stability in alkaline media. This hierarchical architecture is instrumental in exposing the catalytically active sites, boosting mass transport, and speeding up the release of generated hydrogen bubbles from the electrode surface. This research offers a promising way for the electrocatalytic performance of the catalysts toward large-scale water splitting.