Dual Catalytic Activity of Pd-Dispersed MOF for Ammonia-Free Hydrogen Generation from Ammonia Borane and Sodium Borohydride in Aqueous and Methanol Solvents

The development of effective catalysts for hydrogen (H₂) generation from chemical hydrides is essential for advancing hydrogen-based energy technologies. Herein, we synthesized a Pd-dispersed CPO-27 catalyst exhibiting exceptional performance for hydrolysis of two boron-based chemical hydrides, i.e., ammonia borane (AB) and sodium borohydride (SB). The catalyst demonstrated activation energies of 22.7 and 18.12 kJ mol^-1 for AB and SB hydrolysis respectively, confirming its proficient catalytic activity. To comprehensively understand the factors influencing the production of H₂, we systematically investigated the effects of the two hydrides and catalyst concentrations on H₂ evolution rates. Additionally, kinetic isotope effect studies were conducted to determine the rate-determining step of hydrolysis reactions. The Pd@MOF catalyst can efficiently capture released ammonia during AB hydrolysis, addressing a major limitation of this process. Notably, the Pd@MOF catalyst demonstrated its catalytic compatibility with methanol solvent too, exploring its applicability in various reaction environments. Overall, our study highlights the capability of the Pd@MOF catalyst toward H₂ release from diverse complex hydrides in different solvent systems for H₂ generation in clean energy applications.