(263c) Galvanically Displaced Noble Metal Nanoparticles Onto Graphene-CNT Coated Ni-Foam Layered Double Hydroxide Composites for Energy and Storage Conversion Applications

Recent advances in nanotechnology and materials science offers a selection of inexpensive non-precious metal porous electrodes such as nickel for electrochemical applications. Conventional methods of electrolysis to produce H₂ and O₂ gas necessary for proton exchange membrane (PEM) fuel cells, for example, rely on expensive catalysts such as platinum and palladium. Despite the exceptional efficiency of these catalysts, their high cost prevents further industrial scale-up and production. Alternative catalysts such as three-dimensional (3D) nickel foams with high surface area and surface-to-volume ratio are promising materials to reduce kinetic losses and enhance mass transfer rates, respectively. In our study, we investigate the impact of galvanically displaced noble metal salts (HAuCl₄, K₂PtCl₄, and Na₂PdCl₄) onto coated graphene-CNT Nickel and NiFe-LDH (layered double hydroxide) based foams from hydrothermal synthesis, air-controlled electrospraying, electrodeposition, and vacuum filtration techniques as an inexpensive, cost-effective alternative electrodes in capacitators, fuel cells, potential anodes and cathodes for Li-ion and Li-S systems, respectfully. Electrochemical performance of the galvanically displaced noble metal nanoparticles electrosprayed onto coated NiFe-LDH based 3D foams was evaluated using linear sweep voltammetry (LSV) to determine the minimum overpotentials of the catalyst necessary to drive hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Fourier-Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy is used to confirm the presence of the layered double hydroxides with nickel. Scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), and cyclic voltammetry (CV) were used to characterize surface morphology, surface elemental composition, and the electrochemical surface area, respectively. Further, we are investigating the potential for incorporating these Ni-foam composite electrodes into the Lithium-Sulfur and Lithium-Ion batteries to assess cycling performance, initial Coulombic efficiency (ICE), rate capability, charge-transfer and diffusion kinetics.