The transportation industry has seen an increase in demand for green chemistry techniques that produce energy efficiently within hydrogen fuel cells, further eliminating the use of conventional combustion engines that require the use of fossil fuels. The hydrogen from these batteries must be readily produced through a catalyst that is efficient, economical, and safe within the process. These experiments compare the potential viability of using four metal-salt substrates: cobalt (II) chloride, nickel (II) chloride, manganese (II) chloride and iron (II) chloride as efficient and inexpensive catalysts in the presence of sodium borohydride and water. The reactions of each metal salt with NaBH4 were evaluated at different conditions that varied in terms of temperature, pH of solution, and different concentrations of NaBH4. The evolution of hydrogen was measured using a previously described water displacement system [1,2]. The NiCl₂ and CoCl₂ performed best in pH 7 trials at 22 °C with a rate constant of 3.393 L mol^-1 min^-1 and 5.02 L mol^-1 min^-1 respectively. Manganese had the best rate of 3.061 L mol^-1 min^-1 with an increase to pH 8 of solution, while iron (II) chloride had its best trial during increased concentrations of the sodium borohydride with a rate constant of 0.89 L mol^-1 min^-1. Thermodynamic parameters from combined rate constants were determined to show spontaneity of reaction. Nickel, manganese and cobalt were spontaneous reactions at each temperature condition with the exception being iron during the 0°C temperature trial.

References

1. T. Dushatinski, C. Huff, and T. Abdel-Fattah, Applied Surface Science, 385, 282 (2016).

2. C. Huff, T. Dushatinski, A. Barzanji, N. Abdel-Fattah, K. Barzanji, and T. Abdel-Fattah, ECS J Solid State, 6, M69-M71 (2017).