Hydrogen storage and PL properties of novel Cd/CdO shelled hollow microspheres prepared under NH3 gas environment

Here we report the first ever fabrication of metal/semiconductor Cd/CdO shelled hollow microspheres with average diameter of 20-30 mu m via heating cadmium metal powder inside horizontal tube furnace at 500 degrees C for 40 min under ammonia gas flow of 150 sccm. Vapor-solid (VS) based growth mechanism was proposed for the formation of Cd/CdO shelled hollow microspheres (CCOSHMs). The as-prepared product was characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Room temperature photoluminescence (PL) studies exhibited a UV emission band at 395 nm (E = 3.13 eV) which may be ascribed to combined effect of near band edge emission of CdO and Cd related radiative recombination of electrons in s, p conduction band near Fermi surface and the holes in the d bands generated by Xe light excitation. The hydrogen absorption properties of CCOSHMs were investigated at three different temperatures 373, 473, and 573 K. The maximum hydrogen absorption of 1.30 wt% was observed at 573 K which is better than many other materials. This indicates the potential of Cd/CdO shelled hollow microspheres for applications in light emitting devices as well as an interesting material for hydrogen storage research. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.