Core–shell doping of cerium oxide with (Cr–Fe/Co)-B catalyst for enhanced hydrogen evolution in borohydride hydrolysis systems: performance and catalytic efficiency

Herein, we successfully synthesized a CeO₂@(Cr–Fe/Co)-B catalyst for hydrogen generation via NaBH₄ and KBH₄ hydrolysis using a hydrothermal method. To investigate the catalytic activity and hydrogen generation rate (HGR) of the catalyst, various parameters, including the catalyst amount, temperature, reusability, and the concentrations of MOH and MBH₄ (M = Na, K), were tested. The catalyst was comprehensively characterized using FE-SEM, EDX, XRD, BET, TEM, XPS, and FTIR. The CeO₂@(Cr–Fe/Co)-B catalyst exhibited a non-uniform, highly agglomerated, spherical morphology. TEM analysis revealed a core–shell structure with CeO₂ as the core and an 8–16 nm (Cr–Fe/Co)-B shell. BET analysis confirmed the mesoporous nature of the catalyst, with a 27.19 nm pore diameter enabling efficient diffusion and interaction during reactions. The catalyst demonstrated excellent performance, achieving an HGR of 13.05 L g_metal⁻¹ min⁻¹ for NaBH₄ hydrolysis with an activation energy of 18.59 kJ mol⁻¹ and 9.06 L g_metal⁻¹ min⁻¹ for KBH₄ hydrolysis with an activation energy of 30.02 kJ mol⁻¹. Five consecutive experiments were conducted to evaluate the reusability of CeO₂@(Cr–Fe/Co)-B for catalytic hydrolysis of NaBH₄ and KBH₄.