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

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.