A novel core-shell Fe₃O₄@SiO₂/Co-Cr-B magnetic catalyst for efficient and reusable hydrogen evolution from NaBH₄ hydrolysis

This study presents a novel core-shell magnetic catalyst, Fe₃O₄@SiO₂/Co-Cr-B, engineered for efficient and reusable hydrogen generation from NaBH₄ hydrolysis, offering significant advancement in sustainable hydrogen production technologies. The innovation lies in the synergistic integration of a magnetic Fe₃O₄@SiO₂ core with a bimetallic Co-Cr-B shell, which enhances catalytic activity, structural stability, and facile magnetic recovery. Field emission scanning electron microscopy (FE-SEM) revealed a distinctive grape-like morphology resulting from nanoparticle agglomeration, which increased the surface area and active site accessibility. Transmission electron microscopy (TEM) confirmed a well-defined core-shell architecture with a uniform Co-Cr-B shell thickness of 40-50 nm and a consistent particle distribution. These structural features directly contribute to the catalyst's high hydrogen generation rate of 22.2 L g_metal⁻¹ min⁻¹ at 30 °C with a turnover frequency (TOF) of 2110.61 mol_H2 mol_cat⁻¹ h⁻¹. The catalyst demonstrated remarkable stability and maintained >90% of its initial activity after six consecutive reusability tests. These findings highlight the potential of this catalyst for large-scale hydrogen production and offer a promising route for industrial applications with improved efficiency and durability.