Xiayan Yan

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

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.

Separation and characterization of the active species in Ti-doped NaAlH4

The catalytic mechanism of doped complex hydrides for hydrogen storage remains unconfirmed. Here, we report a simple method to separate the active species of Ti-based catalysts in NaAlH(4) by filtration using tetrahydrofuran (THF) as solvent. The results show that the average particle size of the obtained Al-Ti active species is 30-50 nm.

Preparation of Multifunctional Detritiation Catalyst and Design of Detritiation Reactor in Fusion Facility

Abstract Tritium must be strictly defended in tritium systems because of its permeability and radioactivity. Detritiation devices are required in tritium systems, such as the glove box detritiation system, the vent detritiation system, and the air detritiation system in ITER. The method of catalytic oxidation and adsorption is widely used for air detritiation, and metal gas getter is used in glove box detritiation. Here, a Ce-based oxide-loaded honeycomb catalyst is prepared as a multifunctional detritiation catalyst. The properties of the Ce-based oxide and catalyst are characterized by X-ray diffraction, N2-adsorption/desorption (Brunauer-Emmet-Teller method), and H2 temperature programmed reduction. The catalytic performance is tested under both O2-lean and O2-rich atmospheres. Results indicate that the Pt/Ce0.7Zr0.3O2 honeycomb catalyst fully oxidizes H2 at room temperature with high space velocity (3.2 × 104 h−1) when oxygen is sufficient. When oxygen is deficient, H2 is also fully oxidized by the catalyst at 200°C, with the oxygen supplying from the support. A detritiation test using tritium as reactant is also carried out, and the results verify the feasibility for detritiation application. An improved detritiation reactor is designed and built based on the multifunctional catalyst.

Preparation and Properties of Multifunctional Pt/Ce 0.7 Zr 0.3 O 2 Honeycomb Catalyst for Detritiation

Detritiation devices are required in tritium system because of its radioactivity. The method of catalytic oxidation and adsorption is widely used for atmosphere detritiation, but cannot be used in glove box detritiation because of the oxygen-lean atmosphere. A Ce-based oxide-loaded honeycomb catalyst is prepared as a multifunctional detritiation catalyst. The properties of Ce-based support and catalyst are characterized by X-ray diffraction (XRD), N2 adsorption/desorption (Brunauer–Emmet–Teller BET method), and H2 temperature-programmed reduction (H2-TPR), and the catalytic performance is tested under both oxygen-rich and oxygen-lean atmospheres. The Pt/Ce0.7Zr0.3O2 honeycomb catalyst will oxidize hydrogen isotope at room temperature with high space velocity when oxygen is sufficient. When oxygen is deficient, H2 is also fully oxidized by the catalyst at 250 °C, with the oxygen supply from the support reducing.