Bridging chemistry and reactor engineering in NaBH4 hydrolysis: Toward practical hydrogen generators

Hydrolysis of sodium borohydride is currently considered a promising alternative to a controlled storage and production of hydrogen due to its high storage density, handling safety and on-demand generation capability. The aim of this article is to review the hydrolysis reaction, the main types of hydrogen generators from design, reactants form and contact perspective. This paper also addresses the role of catalysts, from noble metals to transition metals and nanostructured materials, as well as their impact on the rate of hydrogen generation, activation energy and stability over time. Some design configurations of the generators, including the main components and reactant feeding strategies, with a focus on hydrogen flow control and integration with PEM fuel cells are presented. Finally, possible mobile applications of these systems are discussed, as well as existing limitations and future direction of development.