Résumé
Ammonia borane NH3BH3 is one of the most popular and studied materials in the field of chemical hydrogen storage. It is an old compound discovered in the 1950s, but it has been rediscovered in the early 2000s as a promising material for chemical hydrogen storage. AB has one of the highest hydrogen density with 19.5 wt% H, and unlike the isoelectronic ethane, it is solid at ambient conditions due to the presence of dihydrogen Hδ+···Hδ‒ bonds.Under heating, pristine AB melts at 100 ± 10 °C and then decomposes. Over the temperature range 100-200 °C, the weight loss is roughly 50 wt% due to the stepwise release of the wanted hydrogen and mainly that of the unwanted volatile products like ammonia, diborane and borazine. We are used to following this by TG (coupled to GC or micro-GC) and DSC analyses. The as-obtained TG and DSC curves are then used as reference curves.Efforts have been dedicated to avoid AB decomposition and favor AB dehydrogenation. A typical objective has been the release of two equivalents of H2 below 100-120 °C such as:x NH3BH3 (s) → 2x H2 (g) + [BNH2]x (s)To that end, one of the strategies has been to nanosize AB by confining it into the porosity of a scaffold (hard-templating method). Nanosized AB does not decompose; it dehydrogenates from 20-50 °C and the dehydrogenation mechanism is different from those of pristine AB. We are used to evidencing this by TG (coupled to GC or micro-GC) and DSC analyses.Nanosized AB can be obtained via soft-templating, which is a method based on the use of surfactants to form inverted micelles. Amine borane adducts, synthesized via an exothermic reaction, are possible surfactants, and these adducts are thermally more stable than the corresponding amines. Recently, we performed a systematic study based on C80 calorimetry and DSC to determine the enthalpies of reaction and of fusion of our amine borane adducts (ANR project called REVERSIBLE).The JCAT52 meeting will be a great opportunity to highlight the importance of thermal analysis in the field of BNH materials for chemical hydrogen storage. For instance, TG analysis can be solely used to see if nanosizing of AB has been successful or not, and this, without using other characterization techniques; this allows us to save time and money.