Hydrogen storage in graphene decorated with Pd and Pt nano-particles using an electroless deposition technique

Graphene samples prepared by the exfoliation of graphitic oxide were decorated with platinum (Pt) and palladium (Pd) by an electroless deposition technique. The obtained composites were attempted to be used as hydrogen storage materials. The composites were characterized by transmission electron microscopy (TEM), Raman spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The porous texture of all graphenes was analyzed using nitrogen adsorption isotherms at 77 K. The hydrogen adsorption was accurately measured by a volumetric adsorption apparatus at 303 K up to 5.7 MPa. The mesopores that originated from the space between exfoliated graphene sheets were observed by nitrogen adsorption isotherms on all graphene samples. Structure investigations reveal that specific surface areas apparently decrease after Pd or Pt decoration. The Pt and Pd nanoparticles of 2-5 nm diameter homogeneously dispersed on the exfoliated graphene sheets and voids of graphene sheets. Experimental results show that Pd or Pt decoration doubles the hydrogen capacity supporting the existence of the hydrogen spillover effect in Pd- or Pt-graphene systems. (C) 2011 Elsevier BY. All rights reserved.