Improvement of the hydrogen storage kinetics of NaAlH4 with Ti-loaded high-ordered mesoporous carbons (Ti-OMCs) by melt infiltration

Abstract

Combination of nanoconfinement and catalyst addition is a promising strategy to enhance the kinetics and reversibility of hydrogen storage in complex hydrides. Herein, Ti-loaded high-ordered mesoporous carbons (Ti-OMCs) were directly synthesized via a solvent evaporation induced self-assembly method (EISA) with in situ crystallization and carbonation technology using phenolic resols, tetrabutyl titanate (Ti(OBu)4) and triblock copolymer F127 as organic carbon sources, Ti sources and templates, respectively. The obtained Ti-OMCs exhibit uniform pore sizes (4 nm), high specific surface area (427.9 m2 g−1) and large pore volumes (0.34 cm3 g−1), which were used to combine catalyst addition and nanoconfinement to improve the hydrogen storage properties of NaAlH4 by melt infiltration. The hydrogen desorption curves show that NaAlH4 with Ti-OMCs exhibits better kinetic properties than both nanocrystalline TiO2 catalysed NaAlH4 and melt-infiltrated NaAlH4 with high ordered mesoporous carbons (OMCs). The hydrogen-release onset temperature of NaAlH4 with Ti-OMCs is reduced to less than 60 °C, and 80% hydrogen is released in less than 20 min. In addition, NaAlH4 with Ti-OMCs exhibit good reversibility and cycling stability, and the optimum rehydrogention temperature is 120 °C.