Enhancement of hydrogen storage capacity and hydrostability of metal–organic frameworks (MOFs) with surface-loaded platinum nanoparticles and carbon black

Abstract

Metal–organic frameworks (MOFs) have generated considerable interest as a potential candidate for hydrogen storage, owing to their extremely high surface-to-volume ratio and low density. However, practical applications have been limited because of low hydrogen storage capacity at room temperature, and of moisture sensitivity of MOFs. To improve hydrogen storage capacity at room temperature and hydrostability under ambient conditions, platinum (Pt) nanoparticles were introduced on the outer surface of MOF-5, Zn4O(1,4-benzenedicarboxylate)3 that was then coated with hydrophobic microporous carbon black (CB) to generate a CB/Pt/MOF-5 composite. To study the chemical composition, morphology, crystallinity, and properties of the synthesized material, various techniques were employed including wide-angle X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma emission spectrometry, high-resolution transmission electron microscopy, and N2 adsorption–desorption analysis. The characterization analyses confirmed the formation of a novel composite designated as CB/Pt/MOF-5 with a highly crystalline structure, and large specific surface area and pore volume. The hydrogen storage capacity (0.62wt.%) of CB/Pt/MOF-5 was superior to that of pristine MOF-5 (0.44wt.%) by 41%; furthermore, CB/Pt/MOF-5 displayed excellent hydrostability under ambient conditions. Overall, these findings indicate that MOF-5 with improved hydrogen storage capacity and hydrostability was successfully synthesized by introducing Pt nanoparticles and a carbon black layer.