Magnetically recyclable Ag/SiO2–CoFe2O4 nanocomposite as a highly active and reusable catalyst for H2 production

In this paper, we reported a facile and effective approach for fabrication of SiO 2 –CoFe 2 O 4 supported dispersed Ag nanoparticles (NPs). The as-synthesized nanocomposites (NCs) were characterized by XRD , TEM, EDX, ICP , XPS and N 2 adsorption-desorption, and used as catalyst for H 2 production from hydrolysis of ammonia borane (AB). A poorly active catalyst of Ag NPs was dramatically converted into a highly active catalyst, in the presence of inactive SiO 2 –CoFe 2 O 4 support. Among all the Ag(0)/SiO 2 –CoFe 2 O 4 NCs catalysts tested, the Ag loading of 0.98 wt% exhibited the highest catalytic activity toward hydrolysis of AB with a highly turnover frequency of TOF = 264 min −1 at room temperature, being higher than that of most reported Ag-based catalysts. Especially, these catalysts can be readily separated from the solution for recycle purpose, and can keep the high activity even after seven times of recycle. These results showed that Ag(0)/SiO 2 –CoFe 2 O 4 NCs prepared in this study are a promising catalyst for hydrogen production from aqueous AB and for developing a highly efficient hydrogen storage system for fuel cell applications .