Synthesis and Electrochemical Study of Graphene-Based Nanocomposites for Hydrogen Sorption and Storage

Abstract

With impending serious concerns associated with climate change and the depletion of fossil fuels, an envisaged hydrogen economy remains a viable alternative for addressing future energy issues. However, the significant technical challenges from vehicular hydrogen storage systems such as weight, efficiency, safety and cost constraints must be properly resolved before a commercial application is possible. Compared to compressed high-pressure and liquid hydrogen storage systems, storing hydrogen in solid systems via chemisorption and physisorption is emerging as a promising approach for hydrogen storage [1-3]. In this presentation, recent advances in the solid-state hydrogen storage with a high volumetric density are highlighted.In addition, graphene-based nanomaterials have been considered as a promising candidate for hydrogen storage due to its lightweight and high surface area [4]. We have synthesized graphene oxide (GO), reduced graphene oxide (rGO) and boron-doped reduced graphene oxide (B-rGO) and investigated their performance for hydrogen storage. To enhance their capacity for hydrogen storage, the fabricated graphene oxide based nanomaterials were further modified with palladium (Pd) nanoparticles. The morphological features, structure and chemical compositions of the synthesized nanomaterials (GO, rGO and B-rGO) and nanocomposites (Pd/GO, Pd/rGO and Pd/B-rGO) were characterized using field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectroscopy, X-ray photoelectron spectroscopy and Raman spectroscopy, showing that Pd nanoparticles were uniformly dispersed on the B-rGO surface. Cyclic voltammetry and galvanostatic charging-discharging technique were employed to probe the hydrogen storage capacity of the graphene based nanomaterials and the nanocomposites. The effect of the boron substitution and the Pd nanoparticle decoration on the hydrogen storage are discussed.