Rare-earth hexaboride 2D nanostructures synthesis and coupling with NaAlH4 for improved hydrogen release

This study investigates two-dimensional REB6 nanostructures formation from a reaction mixture of RE2O3-B2O3-Mg-NaCl composition (RE is Ce, La, Nd, or Eu). The reaction mixture is sealed in a metal cup and is preliminarily heated in argon to reach the flash point. A combustion wave forms on the top surface of the pellet after self-ignition at similar to 650 degrees C. This wave quickly propagates through the sample and increases the sample temperature to 800-950 degrees C, converting the raw mixture into the final product. Processing of the final product leads to the formation of pure hexaboride phases of RE, the particles of which are in the form of nanosheets with a thickness of 50 nm (or less) and a BET surface of 23.8-50.8 m(2)/g. In addition, CeB6 nanosheets were tested as a catalyst in NaAlH4 dehydrogenation/hydrogenation processes. The results demonstrated that the catalytic activity of CeB6 nanosheets increases with higher portions of NaCl.