Fabrication of\nGold and Silver Nanoparticles Supported\non Zinc Imidazolate Metal–Organic Frameworks as Active Catalysts\nfor Hydrogen Release from Ammonia Borane

Well-dispersed Au\nand Ag nanoparticles (NPs) have been immobilized\non a zinc imidazolate metal–organic framework, Zn(mim), using\nthe “one-pot” method and tested as catalysts in ammonia\nborane hydrolysis. The AuNPs@Zn(mim) and AgNPs@Zn(mim) materials were\ncharacterized by FTIR, XRD, ICP-OES, TGA, BET, SEM, and TEM. The AgNPs@Zn(mim)\ncatalyst showed a high yield (98.5%) and high hydrogen generation\nrate (3352.71 mL min<sup>–1</sup> g<sub>Ag</sub><sup>–1</sup>) in NH<sub>3</sub>BH<sub>3</sub> dehydrogenation. The determined\nactivation energies (19.6 kJ mol<sup>–1</sup> for AuNPs@Zn(mim)\nand 38.13 kJ mol<sup>–1</sup> for AgNPs@Zn(mim)) are lower\nthan those for most reported catalysts containing Au/Ag-MOF used in\nthe hydrolysis of NH<sub>3</sub>BH<sub>3</sub>. Moreover, the catalysts\ntested here revealed good stability and reusability, preserving 71.42%\n(AuNPs@Zn(mim)) and 88.23% (AgNPs@Zn(mim)) of their initial catalytic\nactivities after five consecutive cycles. In the case of AgNPs@Zn(mim),\nthe combination of the simple and green synthesis method, low active\nmetal content, relatively low cost, and moderate dehydrogenation conditions\nmakes the material an excellent candidate to produce hydrogen from\nammonia borane.