Ni–Fe–P/Fe–Si electrocatalysts on iron sheets: Regulating surface structure to amorphous heterojunction for excellent oxygen evolution reaction

Nickel iron bimetallic phosphide alloys are a promising electrocatalyst for oxygen evolution reaction (OER). In this work, a highly active Ni–Fe–P/Fe–Si heterojunction electrocatalyst for OER has been synthesized by one-step electrodeposition on iron plate. The synergism effect of Ni–Fe–P alloy and Fe–Si alloy particles after dealloying treatment promotes the construction of nanoflower-like heterogeneous structure with rich lattice defects and exposes a highly open multi-stage nanostructure surface. Furthermore, Si induced the localized electron redistribution optimizes catalytic performance by accelerating electron transfer. The optimal Ni–Fe–P/Fe–Si OER catalyst requires a much low overpotential of 209 mV at a current density of 10 mA cm−2, and 270 mV at a current density of 200 mA cm−2. The prepared Ni–Fe–P/Fe–Si electrode can maintain a current density of 10 mA cm−2 within 24 h, which shows significant electrochemical stability. This study provides a new prospect for the preparation of cost-effective heterogeneous catalysts.