Enhanced Water Dissociation Boosting Sodium Borohydride Hydrolysis on Ru‐Modified CoMoB Catalyst

In the process of sodium borohydride (NaBH₄) hydrolysis catalyzed by the classical Co catalysts, water dissociation is the rate-determining step. The incorporation of Ru lowers the dissociation energy barrier, ensuring rapid proton replenishment and accelerating subsequent hydrogen evolution. Acting as the active site for water dissociation, Ru synergizes with Co, which is the B─H bond dissociation site, to enhance overall catalytic efficiency together.

Abstract

Catalyzed sodium borohydride (NaBH₄) hydrolysis is integral to H₂-supply systems in fuel cells, with Co-B among the most effective catalysts featured with high B─H bond cleavage activity. However, its limited water dissociation capability produces an insufficient proton supply for H₂ generation. In this study, Ru element was introduced with the capability of water deprotonation into the Co-B system, constructing a dual-site catalyst for NaBH₄ hydrolysis. A series of in situ characterizations confirmed accelerated water dissociation kinetics on Ru@CoMoB. Electron transfer between Co and Ru generated a synergistic effect, simultaneously facilitating B─H and H─OH bond cleavage. Consequently, Ru@CoMoB exhibited remarkable catalytic performance, achieving a hydrogen generation rate of 26,936 mL g_cat ⁻¹ min⁻¹ in 10 wt% NaBH₄ at room temperature—approximately 25 times higher than that of the CoMoB control (1,049 mL g_cat ⁻¹ min⁻¹). When implemented in a hydrogen generation system, Ru@CoMoB enabled the stable operation of a 100 W fuel cell.

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