The present Review addresses current developments related to polymer-derived ceramic nanocomposites (PDC-NCs). Different classes of preceramic polymers are briefly introduced and their conversion into ceramic materials with adjustable phase compositions and microstructures is presented. Emphasis is set on discussing the intimate relationship between the chemistry and structural architecture of the precursor and the structural features and properties of the resulting ceramic nanocomposites. Various structural and functional properties of silicon-containing ceramic nanocomposites as well as different preparative strategies to achieve nano-scaled PDC-NC-based ordered structures are highlighted, based on selected ceramic nanocomposite systems. Furthermore, prospective applications of the PDC-NCs such as high-temperature stable materials for thermal protection systems, membranes for hot gas separation purposes, materials for heterogeneous catalysis, nano-confinement materials for hydrogen storage applications as well as anode materials for secondary ion batteries are introduced and discussed in detail.

Hydrazine borane (N₂H₄BH₃) is the novel boron- and nitrogen-based material appearing to be a promising candidate in chemical hydrogen storage. It stores 15.4 wt% of hydrogen in hydridic and protic forms, and the challenge is to release H₂ with maximum efficiency, if possible all hydrogen stored in the material. An important step to realize this ambitious goal is to synthesize HB with high yields and high purity, and to characterize it fully. In this work, we report a 2-step synthesis (salt metathesis and solvent extraction-drying) through which N₂H₄BH₃ is successfully obtained in 3 days, with a yield of about 80% and a purity of 99.6%. N₂H₄BH₃ was characterized by NMR, IR, XRD, TGA and DSC, its stability in dioxane and water was determined, and its thermolysis by-products were characterized. We thus present a complete data sheet that should be very useful for future studies. Furthermore, we propose a discussion on the potential of HB (with H₂ released by either thermolysis or hydrolysis) in chemical hydrogen storage.

A novel boron-modified polysilazane functionalised with Si- and N-bonded methyl groups has been synthesised and characterised by means of FT-IR and NMR spectroscopies as well as elemental analysis. Both Si- and N-bonded methyl groups inhibited extensive cross-linking to yield a tractable polymer which was successfully processed into polymer green fibers by a melt-spinning process. After the shaping processing, the N-bonded methyl groups offered the capability of facile polymer cross-linking in an ammonia atmosphere at 200 °C to increase the ceramic yield of the polymer and avoid inter-fiber fusion. The as-obtained cured fibers were subsequently pyrolysed at 1400 °C in a nitrogen atmosphere to provide amorphous and stable Si_3.0B_1.0C_5.0N_2.4 ceramic fibers with ca. 1.3 GPa in tensile strength, ca. 170 GPa in Young's modulus and ca. 23 μm in diameter.