FeNi/Ni2P nanoparticles encapsulated in nitrogen-doped porous carbon: efficient electrocatalysts for oxygen evolution reaction

Abstract

Efficient, stable, and cost-effective electrocatalysts for the oxygen evolution reaction (OER) are crucial for advancing large-scale water electrolysis for hydrogen production. In this study, we present a novel electrocatalyst featuring FeNi/Ni₂P nanoparticles encapsulated in nitrogen-doped porous carbon (FeNi/Ni₂P@NC). The catalyst was prepared by pyrolyzing low-cost anion exchange resin (AER) loaded with non-precious metal salts, followed by phosphidation. The FeNi/Ni₂P@NC catalyst benefits from the synergistic effects of the FeNi alloy, Ni₂P phosphide, and N-doped porous carbon, which together enhance the number of active sites available for the OER. The large surface area of the material optimizes both electron transfer and mass diffusion pathways, leading to remarkable OER performance. At a current density of 10 mA cm⁻², FeNi/Ni₂P@NC demonstrates an overpotential of 323 mV and a Tafel slope of 60.3 mV dec⁻¹, significantly outperforming the Tafel slope of 89.3 mV dec⁻¹ observed for the precious metal RuO₂. Furthermore, the carbon shell layer effectively mitigates nanoparticle corrosion, thereby improving the long-term stability of the catalyst. This study presents a novel approach for developing efficient, stable, and cost-effective carbon-based catalysts for water electrolysis.

Graphical abstract