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High entropy alloy (HEA) has recently gained attention as one of the promising materials for catalytic field because of its unique structure and multi-constituent synergy catalytic applications due to its diverse element composition and multi-constituent synergy that offered excellent thermal stability, catalytic activity and corrosion resistance. In the work, we introduce the facile preparation of a self-supporting HEA-FeMnCuCo via one-step electrodeposition method, followed by generating HEA multicomponent hydroxyl oxide via a corrosion engineering approach to acquire an efficient and stable alkaline electrolytic catalyst. The prepared catalyst exhibits a remarkable catalytic performance with the overpotentials of 226 mV at current densities of 10 mA cm−2, and a low Tafel slope of 58.2 mV·dec −1. And the high activity is attributed to the formation of transition metal elements (Ni/Fe/Co) with high oxidation states by a corrosion engineering, which increase the active sites and reduced the initial potential of oxygen evolution reaction. Additionally, the HEA catalyst exhibits an excellent long-term OER stability, lasting over 100 h at 50 mA cm−2. • The unique corrosion engineering improves catalytic performance. • The special cauliflower shape increases the active area. • The Ni–Fe–Co with high oxidation state are the true active sites of OER. [ABSTRACT FROM AUTHOR]

Establishing efficient nano-porous electrocatalysts for facilitating electron transfer is a one of the useful ways for enhance water splitting. Herein, Ni-Fe-Cu-Co-W high entropy alloy (NFCCW-HEA) electrocatalysts on the iron sheet substrate have been successfully prepared by a simple and efficient one-step electrodeposition method. High entropy alloys have a variety of active sites and unique atomic scale synergies, which makes the catalyst have good catalytic performance and stability. Meanwhile, the HEA coating like cauliflower by electrodeposition can provide more attachment sites, and significantly upgrade the OER catalytic activity. NFCCW-HEA catalysts exhibit an excellent overpotential of 247.3 mV under the current density of 10 mA·cm−2, and a low Tafel slope of 62.9 mV dec−1. The electrocatalyst shows long term stability of electrolysis for over 24 h in 1 mol·L−1 KOH alkaline solution, which shows good stability. We expect to provide a new idea for the preparation of nano porous high entropy alloy electrocatalysts by one-step electrodeposition technology. [Display omitted] • The nano-porous Ni-Fe-Cu-Co-W high entropy alloy electrocatalysts are prepared by a simple and efficient one-step electrodeposition method. • The formation mechanism of catalysts is carefully studied. • The unique cauliflower like nano-sheets can significantly improve the OER catalytic performance. • The synergy of multiple components • Explore different active sites [ABSTRACT FROM AUTHOR]

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. [Display omitted] • A new nanoflower shaped heterogeneous electrocatalyst: Ni–Fe–P/Fe–Si. • A excellent electrocatalytic activity of OER: 209 mV/10 mA cm−2 in 1 M KOH. • A new strategy design high activity and low-cost electrocatalysts. [ABSTRACT FROM AUTHOR]