Hamamelis-like K₂Ti₆O₁₃ Synthesized by Alkali Treatment of Ti₃C₂ MXene: Catalysis for Hydrogen Storage in MgH₂

Abstract

An intriguing Hamamelis-like structure of K2Ti6O13 with branches of 10–20 nm in length is synthesized by alkali treatment of Ti3C2 MXene. It exhibits strong catalytic activity for hydrogen desorption from MgH2. The initial dehydrogenation temperature (175 °C) of a composite of MgH2 with 5 wt % K2Ti6O13 is 112 °C below that of pristine MgH2. Isothermal dehydrogenation analysis indicates that the composite releases 6.7 wt % hydrogen at 280 °C within 3 min, and with 2.7 wt % hydrogen being released at 200 °C. The activation energy of this material (105.67 kJ mol–1) is 69.67 kJ mol–1 lower than that of pristine MgH2. Its strong hydrogen adsorption/desorption capacity is attributed to the synergies of catalytic effects of KMgH3, TiO, and Ti, which originated from K2Ti6O13. These findings make a contribution to study the H2 storage properties of metal hydrides doped with Ti3C2 MXene derivatives.

Combinations of V2C and Ti3C2 MXenes for Boosting the Hydrogen Storage Performances of MgH2

“…MXenes have shown possible applications in energy conversion and storage and catalysis. MXenes and their derivatives also have positive effects on the hydrogen storage materials. − In 2016, Liu et al made the first attempt to utilize two-dimensional Ti 3 C 2 to significantly enhance the hydrogen sorption behavior of MgH 2 . It was shown that MgH 2 –5 wt % Ti 3 C 2 starts releasing hydrogen at 185 °C and can reach a capacity of 6.2 wt % within 60 s at a constant temperature of 300 °C, while it can absorb 6.1 wt % of hydrogen in 30 s at a temperature of 150 °C.…”

Engineering the Oxygen Vacancies in Na2Ti3O7 for Boosting Its Catalytic Performance in MgH2 Hydrogen Storage

“…As clearly shown in the gure, the MgH 2 + 5Na , respectively. Subsequently, the dehydrogenation dynamics were investigated according to the nine kinetic models proposed in our previous report 24 . It should be noted that f(α) = A(t/t 0.5 ), where t 0.5 is the time when α = 0.5 and A is a constant depending on the kinetic model, and f(α) is a term for the reaction rate depending on the reaction mechanism.…”

“…Among all catalysts investigated, Ti-based materials are commonly recognized as the best-performing ones and have been widely used to improve the hydrogen storage performances of the MgH 2 system, via signi cantly reducing the activation energy of de/ab-hydrogenation of MgH 2 while unchanging the enthalpy and entropy in the hydride formation process 22 . In particular, titanate materials, such as NiTiO 3 23 , K 2 Ti 6 O 13 24 , TiVO 3.5 25 , etc., have attracted more attentions in MgH 2 hydrogen storage system.…”

Dual-Ion Substitution-Induced Unique Electronic Modulation to Stabilize an Orthorhombic Lattice towards Reversible Hydrogen Isotope Storage

“…Hydrogen storage materials have drawn significant attention because of their importance in the development of sustainable energy. − In recent years, the hydrogen isotopes storage materials for handling the fuels (deuterium and tritium) of a nuclear fusion system in the International Thermonuclear Experimental Reactor (ITER) − are extracting extensive research. ZrCo alloy is considered as the most promising material to be used in a hydrogen isotopes storage and delivery system (SDS) in ITER due to its excellent hydrogen storage performances, ,− such as low equilibrium hydrogen pressure under room temperature, prominent de-/hydriding kinetics, and moderate desorption temperature for the delivery of 100 kPa hydrogen.…”