The limited supply of nonrenewable resources, such as oil and natural gas, as well as the environmental impacts these fuel sources generate has prompted research into the field of renewable and clean sources of energy. A viable candidate to replace nonrenewable resources could come in the form of hydrogen gas, which is recyclable in nature.¹ Hydrogen gas is also a more environmentally conscious alternative to fossil fuels, since it generates no harmful emissions unlike fossil fuels.^2-3 One obstacle preventing hydrogen gas from being produced on a global scale, as with gasoline, is due to the difficulties associated with harnessing and storing pressurized gas. A solution to this problem can be found in metal hydrides, which are known for their hydrogen releasing capabilities.⁴ The most favorable metal hydride is sodium borohydride (NaBH₄) due to its high hydrogen content (10.8% wt) and its exceptional energy density.⁴ Sodium borohydride can generate as much as 4 moles of hydrogen gas when reacted with water, however, this reaction proceeds slowly. To accelerate the oxidation of aqueous sodium borohydride, a catalyst is needed. It has been found that graphene supported transition metal catalysts, like silver, can be used to catalyze this reaction.^1-5 In this experiment, silver nanoparticles coupled with graphene and graphene oxide scaffold supports were used as the catalytic material for the hydrogen generation reactions. The silver nanoparticles catalyzed reaction was found to preform best under a pH of 7 and a temperature of 30°C producing a rate constant of 0.0026 mol^-1sec^-1.

References

1. Liu, B.; Li, Z. A review: Hydrogen generation from borohydride hydrolysis reaction. Journal of Power Sources 2009, 187, 527–534.
2. Kojima, Y.; Suzuki, K.-I.; Fukumoto, K.; Sasaki, M.; Yamamoto, T.; Kawai, Y.; Hayashi, H. Hydrogen generation using sodium borohydride solution and metal catalyst coated on metal oxide. International Journal of Hydrogen Energy 2002, 27, 1029–1034.
3. Abdel-Fattah, T. M.; Wixtrom, A. Catalytic Reduction of 4-Nitrophenol Using Nanoparticles on Carbon Nanotubes. ECS J. Solid State Sci. Technol. 2014, 3, M18-M20.
4. Schlesinger, H.; Brown, H.; Finholt, A.; Gilbreath, J.; Hoekstra, H.; Hyde, E. Sodium Borohydride, Its Hydrolysis and its Use as a Reducing Agent and in the Generation of Hydrogen. J. Am. Chem. Soc. 1952, 75, 215-219.
5. Kochkar, H., Aouine, Ghorbel, A.,Berhault, G. Shape-Controlled Synthesis of Silver and Palladium Nanoparticles Using β-Cyclodextrin. Journal of Physical Chemistry 2011, 115, 11364-11373.