Recent enhancement of ammonia borane hydrolysis using spinel-type metal ferrites nano-catalysts

Owing to the huge energy content of hydrogen, making it a solution of current energy problems, the development of economic and active catalysts to release hydrogen from storage materials such as ammonia borane (hydrogen content of 19.6 wt%) has attracted great attention. Therefore, in this study, magnetically recyclable metal ferrite nano-particles were used for the first time as catalysts for hydrogen generation from the hydrolysis of ammonia borane (NH3BH3) under moderate conditions. Four metal ferrite nano-particles (CuFe2O4, MnFe2O4, NiFe2O4 and ZnFe2O4) were prepared and characterized using different analysis tools; thermal gravimetric analysis, X-ray diffraction, BET Surface area, transmission electron microscope. The results of ammonia borane (AB) hydrolysis indicate that the hydrogen generation rate increases with both hydrolysis temperature and catalysts amount to reach 23.5 ml/min at 45 °C & 6 mg cat. Among the tested ferrite catalysts, MnFe2O4 was found to be the best one for AB hydrolysis as the complete conversion was achieved in only 20 min. The remarkable conclusion is that, beside the high activity and low activation energy of those catalysts in AB hydrolysis, spinel metal ferrite catalysts can be easily separated from the reaction container for recycling purposes, and remain highly active even after 5 times of recycling under ambient atmosphere.