Core-shell NaBH @Ni Nanoarchitectures: A Platform for Tunable Hydrogen Storage

The core-shell approach has surfaced as an attractive strategy to make complex hydrides reversible for hydrogen storage; however, no synthetic method exists for taking advantage of this approach. Here, a detailed investigation was undertaken to effectively design freestanding core-shell NaBH @Ni nanoarchitectures and correlate their hydrogen properties with structure and chemical composition. It was shown that the Ni shell growth on the surface of NaBH particles could be kinetically and thermodynamically controlled. The latter led to varied hydrogen properties. Near-edge X-ray absorption fine structure analysis confirmed that control over the Ni /Ni B concentrations upon Ni reduction led to a destabilized hydride system. Hydrogen release from the sphere, cube, and bar-like core-shell nanoarchitectures occurred at around 50, 90, and 95 °C, respectively, compared to the bulk (>500 °C). This core-shell approach, when extended to other hydrides, could open new avenues to decipher structure-property correlation in hydrogen storage/generation.