Synthesis and characterization of activated carbon-platinum composites and effect on hydrogen storage rate

Abstract

A novel, facile and low temperature process for activated carbon-platinum (AC-Pt) composites has been developed in the absence of additive reducing agents. By varying the pH value and heating approach, the size and amounts of loading Pt nanoparticles could be tuned. According to the results of nitrogen adsorption analysis, small angle X-ray scattering profiles, X-ray diffractometer spectrometer patterns, inductively coupled plasma mass spectrometry and field emission scanning electron microscope images, it was indicated that lower pH value and higher reaction temperature would conduce to larger Pt nanoparticles as well as greater amounts. Attributing to the results of nitrogen adsorption analysis, the impregnating condition of Pt nanocrystals also obviously influenced the specific surface area and the pore structure of AC-Pt composites, which evidently resulted in dissimilar hydrogen adsorption behavior. In this research, the hydrogen storage rate was measured using high pressure thermo-gravimetric analyzer under flow condition. It was discovered that small Pt nanoparticles uniformly distributed in pores might aid gas diffusion of hydrogen molecules and surface diffusion of atomic hydrogen in pores of AC via the so-called hydrogen spillover phenomenon and enhance higher adsorption rate, even at lower Pt contents. © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.