Abstract
Cobalt-chromium carbide-embedded carbon nanofibers (nanocomposite) were prepared via electro-spinning of a solution containing cobalt acetate tetrahydrate (CoAc), chromium (II) acetate dimer monohydrate (CrAc), and polyvinylpyrrolidone (PVP) followed by carbonization. Carbonization was achieved at a low temperature (850 degrees C, Ar gas, 6h) as the nanocomposite contained metal carbide. The synthesized nanocomposite was analyzed using advanced analytical techniques. The catalytic activity of the nanocomposite in hydrogen liberation through the hydrolysis of aqueous ammonia borane (AB) solution was evaluated and compared to those of cobalt/carbon nanofibers (Co/CNFs) and cobalt nanoparticles (Co NPs). The synthesized nanocomposite showed the highest catalytic activity at 0.2475 mol/min compared to Co/CNFs, 0.174 mol min(-1), and Co NPs, 0.09 mol min(-1). The synthesized nanocomposite also showed high stability; it was reused six times without makeup, reactivation, or regeneration. Kinetic studies showed that the rate of AB hydrolysis is dependent on the catalyst concentration and temperature; the value of turn over frequency (TOF) and the activation energy for the prepared nanocomposite were found to be 25.78 mol(H2) min(-1)(mol(metal)(-1)) and similar to 24.2 kJ mol(-1), respectively. (C) 2017 Elsevier B.V. All rights reserved.