The present study examines the interaction of hydrogen and nitrogen plasmas with gallium in an effort to gain insights into the mechanisms behind the synergetic effect of plasma and a catalytic metal. Absorption/desorption experiments were performed, accompanied by theoretical-computational calculations. Experiments were carried out in a plasma-enhanced, Ga-packed, batch reactor and entailed monitoring the change in pressure at different temperatures. The results indicated a rapid adsorption/dissolution of the gas into the molten metal when gallium was exposed to plasma, even at a low temperature of 100 °C. The experimental observations, when hydrogen was used, indicate that gallium acts as a hydrogen sink in the presence of plasma. Similar results were obtained with Ga in the presence of nitrogen plasma. In addition, density functional theory calculations suggest a strong interaction between atomic hydrogen and molten gallium. This interaction is described as a high formation of Ga-H species on the surface, fast diffusion inside the metal, and a steady state concentration of the gas in the bulk.
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The authors acknowledge partial support from the National Science Foundation (NSF EPSCoR) 1355438 and the Conn Fellowship to Maria Carreon from the Conn Center for Renewable Energy Research.
See supplementary material at https://doi.org/10.1116/1.5004540 for details on the experimental set up and the Ga-H interaction modeling.
Carreon, Maria L.; Jaramillo-Cabanzo, Daniel F.; Chaudhuri, Indira; Menon, Madhu; and Sunkara, Mahendra K., "Synergistic Interactions of H2 and N2 with Molten Gallium in the Presence of Plasma" (2017). Physics and Astronomy Faculty Publications. 592.