Synthesis of Palladium Nanoparticles Supported over Fused Graphene-like Material for Hydrogen Evolution Reaction

Abstract

The search for a clean abundant energy source brought hydrogen gas into the limelight; however, the explosive nature of the gas brings up issues with its storage. A way to mitigate this danger is through the storing of hydrogen in a hydrogen feedstock material, which contains a large percentage of its weight as hydrogen. Sodium borohydride is a feedstock material that gained a lot of attention as it readily reacts with water to release hydrogen. This study explored a novel composite composed of palladium nanoparticles supported on a sugar-derived fused graphene-like material support (PdFGLM) for its ability to catalyze the reaction of sodium borohydride in water. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) were used to characterize and determine the size and shape of the catalyst used in this study. The XRD study detected the presence of palladium nanoparticles, and the EDS date confirmed the presence of 3% palladium nanoparticles. The TEM result shows the palladium nanoparticles of 5.5 nm incorporated to the graphene-like material layers. The composite contained approximately 3% palladium. In the hydrogenation reactions, it was observed that optimal reaction conditions included lower pHs, increased temperatures, and increased dosages of sodium borohydride. The reaction had the greatest hydrogen generation rate of 0.0392 mL min−1 mgcat−1 at pH 6. The catalyst was tested multiple times in succession and was discovered to increase the volume of hydrogen produced, with later trials indicating the catalyst becomes more activated with multiple uses. The activation energy of the reaction as catalyzed by PdFGLM was found to be 45.1 kJ mol−1, which is comparable to other catalysts for this reaction. This study indicates that this catalyst material has potential as a sustainable material for the generation of hydrogen.