Nickel-Platinum Nanoparticles Supported on Zeolitic Imidazolate Framework/Graphene Oxide as High-Performance Adsorbents for Ambient-Temperature Hydrogen Storage.

A facile liquid impregnation method followed by a reduction treatment was applied for loading transition metals nickel, nickel-platinum, and platinum into zeolitic imidazolate framework (ZIF-8)/graphene oxide (GO) as potential adsorbents for ambient-temperature hydrogen storage. These materials have been characterized by powder X-ray diffraction, infrared spectra, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma-emission spectroscopy, and gas adsorption apparatus for their physical and chemical properties. The metal-doped ZIF-8/GO composites maintained the morphology of pristine ZIF-8, although their specific surface areas significantly decreased. The metal nanoparticles in the corresponding composites have average diameters of 4.2–5.1 nm, and uniformly located on the external surface and edges of ZIF-8/GO network. Hydrogen adsorption amounts on metal-doped samples were enhanced by factors of 2.3–3.8 times over ZIF-8 at 298 K due to the spillover effect. Notably, the Pt-doped ZIF-8/GO sample seems to be the best adsorbent for hydrogen storage because of the higher catalytic reactivity of platinum than nickel.