Self‐Reconstructed Spinel Surface Structure Enabling the Long‐Term Stable Hydrogen Evolution Reaction/Oxygen Evolution Reaction Efficiency of FeCoNiRu High‐Entropy Alloyed Electrocatalyst

Abstract

High catalytic efficiency and long‐term stability are two main components for the performance assessment of an electrocatalyst. Previous attention has been paid more to efficiency other than stability. The present work is focused on the study of the stability processed on the FeCoNiRu high‐entropy alloy (HEA) in correlation with its catalytic efficiency. This catalyst has demonstrated not only performing the simultaneous hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) with high efficiency but also sustaining long‐term stability upon HER and OER. The study reveals that the outstanding stability is attributed to the spinel oxide surface layer developed during evolution reactions. The spinel structure preserves the active sites that are inherited from the HEA's intrinsic structure. This work will provide an insightful direction/pathway for the design and manufacturing activities of other metallic electrocatalysts and a benchmark for the assessment of their efficiency–stability relationship.

High-entropy alloys in electrocatalysis: from fundamentals to applications

“…In a recent study, Huang et al investigated the stability processes of the FeCoNiRu HEA during the long-term OER stability test. 326 Following the OER stability test (10 mA cm −2 for 40 h), SEM and TEM revealed the presence of a thin oxide layer that appeared to cover the entire surface of the FeCoNiRu HEA. High-resolution TEM further identified this oxide layer as a spinel structure of (Fe, Ni)(Fe, Co, Ru) 2 O 4 (Fig.…”

Challenges and opportunities in 2D high‐entropy alloy electrocatalysts for sustainable energy conversion

“…Reproduced with permission from ref. 75 Copyright 2023, Wiley. (D) The p K sp and the pH value at which ions (0.1 mol L −1 ) begin to precipitate.…”

“…prepared a FeCoNiRu HEA electrocatalyst derived from a high‐entropy metal‐organic framework (HE‐MOFs) precursor (Figure 4C). 75 The carbon skeleton derived from the MOF precursor exhibited a porous structure with ample channels, enabling rapid transfer of the reactive material. This unique structure helped to slow down the growth of nanoparticles (NPs) and prevent their aggregation.…”

An efficient Ni3S2–Ni electrode constructed by a one-step powder metallurgy approach for the hydrogen evolution reaction

“…However, as a noble metal catalyst, Pt is expensive and scarce, which limits its wide application, and thus it is urgent to find a cheap and renewable non-noble metal catalyst to replace Pt. 13–15 In the last few decades, transition metals, alloys 16,17 and transition metal compounds, such as transition metal borides, 18 carbides, 19,20 selenides, 21,22 nitrides, 23–25 oxides, 26 phosphides, 27,28 and sulfides, 29,30 have been widely reported for the HER due to their unique electronic properties. For example, Cao et al 25 synthesized Mo(N)/Co nanosheets via hydrothermal synthesis, excessive corrosion, heat treatment and nitridation.…”