Enabling easy and efficient hydrogen release below 80 °C from NaBH4 with multi-hydroxyl xylitol

NaBH₄ has been widely considered as a low-cost hydrogen storage material with high gravimetric hydrogen capacity of about 10 wt%. However, its strong thermodynamic stability severely hinders the application of NaBH₄ to obtain hydrogen. In this study, multi-hydroxyl xylitol, for the first time, was chosen as a protic hydrogen carrier to destabilize and react with NaBH₄. The NaBH₄-xylitol composites were easily prepared through hand-milling, which leads to the fast liberation of hydrogen from moderate temperatures lower than 80 °C with more than 3.6 wt% hydrogen desorption capacity. Besides, over 80% of hydrogen could be efficiently released in NaBH₄-xylitol composite. The dehydrogenation process is proved to be completely impurity-free and controllable by altering the NaBH₄/xylitol ratios and operating temperatures. The reaction between NaBH₄ and xylitol is investigated to be similar to an alcoholysis procedure, however no observable liquid phase takes place before and after the dehydrogenation of NaBH₄-xylitol composite, showing a great potential to produce hydrogen under low temperatures through solid-state carriers.