Solid-state synthesis of amorphous TiB2 nanoparticles on graphene nanosheets with enhanced catalytic dehydrogenation of MgH2.

Abstract: A bi-component catalyst TiB2/GNSs (GNSs is the abbreviation of graphene nanosheets) is synthesized by a solid-state method. Microstructural characterizations based on SEM (scanning electron microscopy), TEM (transmission electron microscopy) and N2 physisorption show that the size of TiB2/GNSs catalyst is at nanoscale (20–30 nm) with a surface area of 84.69 m2 g−1. The TiB2/GNSs nanoparticles ball milled with MgH2 and exhibit enhanced catalytic effects on the dehydrogenation properties of MgH2 compares to TiB2 and GNSs individually. DSC (differential scanning calorimetry) measurements confirm that the peak desorption temperature of MgH2-5 wt%TiB2/GNSs composites can be lowered more than 44 °C than the pure as-milled MgH2. And the dehydrogenation kinetics of TiB2/GNSs-doped MgH2 is severalfold acceleration compares to the pure as-milled MgH2. It is proposed that the TiB2/GNSs nanoparticles could significantly enhance the intimate interface between TiB2/GNSs and hydride, therefore, provide more active “catalytic sites” and H “diffusion channels” to reduce the dehydrogenation temperature and improve the dehydrogenation kinetics of MgH2. The synergistic effect of nano-GNSs and TiB2 nanoparticles contributes to the highly efficient for dehydrogenation of MgH2-5wt%TiB2/GNSs composites. [Copyright &y& Elsevier]