Magnesium Supported on Nickel Nanobelts for Hydrogen Storage: Coupling Nanosizing and Catalysis

Magnesium nanoparticles with the mean particle size of similar to 18 nm were synthesized through the thermal decomposition of di-n-butylmagnesium using Ni nanobelts as a catalyst and support with the aim of improving the hydrogen storage properties of magnesium by coupling nanosizing and catalysis. Full hydrogenation of the magnesium nanoparticles was achieved at a low temperature of 100 degrees C, and hydrogen release occurred at similar to 230 degrees C. The material showed fast hydrogen absorption with good structural stability during cycling. Hydrogen desorption occurred in 200 min at 250 degrees C. These enhanced hydrogen storage properties were assigned to a lower activation energy (69.2 +/- 2.5 kJ mol(-1)H(2)), and the remarkably low enthalpy of hydrogenation (34.4 +/- 5.4 kJ mol(-1) H-2) although partially compensated by a reduced entropy of 76.9 +/- 5.4 J K-1 mol(-1)H(2). The improvement of both kinetics and thermodynamics is believed to result from the coupling effects of nanosizing and catalysis.