Graphitic nanofibers supported NiMn bimetallic nanoalloys as catalysts for H2 generation from ammonia borane

Abstract

Bimetallic nickel manganese nanoalloy-decorated graphitic nanofibers were prepared using electrospinning. The introduced catalysts were explored as an effective and inexpensive catalyst for H2 generation from ammonia borane using hydrolysis. Standard techniques were used to determine the morphology and chemical composition of the nanofibers. Characterization indicated successful formation of bimetallic nickel-manganese-decorated graphitic nanofibers. Introduced effective catalysts showed a high reusability for H2 generation using ammonia borane hydrolysis at low concentrations and temperatures. All formations of the introduced catalysts demonstrated a higher catalytic activity in H2 generation than nickel-decorated carbon nanofibers. Samples composed of 55 wt% nickel and 45 wt% manganese showed the best catalytic activity compared with other formulations. Initial turnover frequency (TOF) of this sample was 58.2 min−1, twice the TOF of the manganese-free catalyst. Kinetics and thermodynamics revealed that the catalyst concentration followed the pseudo-first order reaction while the ammonia borane concentration follow the pseudo-zero order reaction, providing activation energy of 38.9 kJ mol−1.