Pt-doped graphene oxide/MIL-101 nanocomposites exhibiting enhanced hydrogen uptake at ambient temperature

Nanocomposites of Pt-doped graphene oxide (GO) and a chromate-organic framework (MIL-101) were prepared through the in situ solvent-thermal method. The parent materials and all composites have been characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, and gas adsorption analysis. The results indicated that the incorporation of a Pt/GO component did not prevent the formation of MIL-101 units. However, the crystallinities, morphologies, and surface areas of the composites were affected obviously by the Pt/GO content. The significant enhancement by a factor of 1.57-2.69 of hydrogen storage capacities at ambient temperature and 10 bar for the composites can be attributed reasonably to the spillover mechanism in such a system, in which Pt nanoparticles act as the spillover source of hydrogen molecules, while GO and MIL-101 act as the primary and secondary receptors, respectively.