Highly Dispersed Cobalt Phosphide in Zeolites: Unlocking Superior Efficiency in Ammonia Borane Hydrolysis

Ammonia borane (AB) is a promising material for chemical hydrogen storage; however, efficient hydrogen generation often relies on expensive noble metal catalysts. Herein, highly dispersed sub-3 nm transition metal phosphide nanoparticles supported in amino-functionalized Beta zeolites are developed using a facile impregnation method. The optimized Co-Co₂P/NH₂-Beta catalyst, benefiting from the structural modulation of cobalt phosphides and their interaction with the Brønsted acid sites of zeolites, achieves a high hydrogen generation rate of 240.0 mol_H2 mol_Co ^-1 min^-1 at 298 K during AB hydrolysis. Both experimental results and theoretical calculations emphasize that Co₂P exhibits stronger adsorption and lower dissociation energy barriers for both H₂O and AB compared to CoP. Furthermore, the introduction of metallic Co and/or phosphorus vacancies into Co₂P through H₂ reduction significantly enhances catalytic efficiency. This work provides valuable insights for the design of high-performance zeolite-supported ultrasmall TMP catalysts, paving the way for more efficient chemical hydrogen storage solutions.