Gold Nanoparticles Supported over Low-Cost Adsorbents for Hydrogen Generation from a Solid Hydrogen Feedstock

Abstract

Due to the rising concern of global warming and the limited supply of fossil fuels, hydrogen gas production for use as a clean and renewable energy source has been a rapidly growing field of research. A significant amount of work has been done in generating hydrogen gas from water [1-3]. However, this is an energy intensive process. Solid chemical storage of hydrogen using metal hydrides has been proposed as an attractive alternative. Sodium borohydride is considered one of the most viable hydrogen storage materials because it provides a safe and practical means of producing hydrogen and has a high hydrogen content (10.7% wt). Sodium borohydride produces hydrogen by slowly reacting with water to evolve 4 moles of hydrogen gas [3]. While a slow reaction is favorable for reduction, the use of sodium borohydride to produce hydrogen gas for energy generation necessitates the use of catalysis to accelerate the reaction to an appreciable rate. A significant amount of research has been conducted searching for catalysts of such reactions, often finding noble metals to be the most efficient. Nobel metals are often expensive, therefore price must be considered when deciding on a catalyst. A cost effective strategy to create noble metal catalysts is to synthesize nanoparticles of the metal of interest and adsorb them to low-cost supports. Gold nanoparticles affixed to activated carbon and glasswool were tested for catalytic activity in the hydrogen evolution reaction of aqueous sodium borohydride and compared against the catalytic activity of uncoated activated carbon and glasswool supports. The evolved gas was measured through the use of a water-displacement system, Ohaus microbalance, and mass logging software. Preliminary data suggests that the gold nanoparticle supports are more efficient at generating hydrogen than non-coated substrates.