# Micro‐Petal Cobalt‐Doped FeMoB Framework for Efficient Hydrogen Generation in Ampere‐Level Water Electrolysis

## TL;DR

A new cobalt-doped FeMoB micro-petal framework is developed for efficient hydrogen production through water electrolysis, showing high performance and stability.

## Contribution

A novel Co-doped FeMoB micro-petal framework is introduced for efficient and stable water electrolysis.

## Key findings

- The Co/FeMoB micro-petal system achieves a cell voltage of 2.87 V at 2000 mA cm−2 and maintains stability for 250 hours.
- The hybrid Co/FeMoB electrode delivers a record-low cell voltage of 2.26 V at large current densities.
- The enhanced performance is attributed to electronic/structural modulation, elemental synergism, and expanded active surface.

## Abstract

Efforts to develop highly efficient, affordable replacements for noble/precious metal electrocatalysts for hydrogen generation via water electrolysis continue to face critical challenges in addressing global energy and environmental concerns. Herein, Co‐doped FeMoB micro‐petal (MP) novel framework is demonstrated via a two‐step hydrothermal approach, followed by thermal annealing treatment. The optimized Co/FeMoB MP exhibits significantly enhanced HER/OER performance, requiring only 54/257 mV at 100 mA cm−2 in 1 m KOH, ranking it among the most promising dual‐functional electrocatalysts. For overall water‐splitting, the bifunctional MP (− /̸̸ / +) system delivers an ultra‐low cell voltage of 2.87 V at 2000 mA cm−2 and maintains continuous stability for 250 h at 600 mA cm−2. In addition, the hybrid Co/FeMoB electrode delivers a record‐low cell voltage of 2.26 V at large‐current‐density in 6 m KOH at 60 °C, demonstrating excellent feasibility for large‐scale hydrogen production under harsh industrial conditions. The superior multifunctional properties of Co‐doped FeMoB are attributed to the electronic/structural modulation by 3d‐block metal effects, elemental synergism, abundant active sites, polycrystallinity, and expanded electrochemically active surface. This study demonstrates that a trace level of the introduced Co into the active bimetallic FeMoB matrix can significantly enhance its electrocatalytic activity toward next‐generation and commercial H2O electrolysis.

Micro‐petal (MP) bifunctional system exhibits superior water electrolysis performance, delivering 2.87 V at a large‐current‐density (LCD) of 2000 mA cm−2, which is comparable to the benchmark setup. Significantly, the hybrid configuration achieves a record‐low 2‐E cell voltage of 2.26 V at LCD. Further, the bifunctional MP demonstrates remarkable stability, maintaining continuous operation for 250 h under 600 mA cm−2 in 1/6 M KOH.