Room Temperature Hydrogen Absorption of Mg/MgH₂ Catalyzed by BaTiO₃

Abstract

This paper seeks to present notable insights into the catalytic behavior of a ferroelectric BaTiO3 nanomaterial at the boundary plane in the separation of MgH2 starting from 185 °C. The synergy between mechanical milling and enhanced electronic distribution at the surface of BaTiO3 aided magnesium to a remarkable absorption of 4.5 wt % H2 at room temperature under 30 bar within 20 h. The composite released H2 ∼ 5.7 wt % in 15 min at 310 °C and ∼5.1 wt % in 90 min at 250 °C. The lowered activation energy of decomposition was calculated to be ∼60 kJ/mol with a decomposition enthalpy of 72.3 kJ/mol-H2. The composite reversibly produced ∼5.7 wt % H2 across 20 cycles in less than 120 h at 300 °C. As revealed by detailed experimental results, the interplay between +4 and +3 states of titanium at “111” twin boundaries of BaTiO3, and the formation of oxygen vacancies, play an important role in improving the sorption kinetics and the reversibility of Mg/MgH2. Meanwhile, the anomalous ferroelectric character of the +2 state of barium around Ti–O and Mg after milling of BaTiO3 is also believed to slightly enhance MgH2 desorption enthalpy via a chemisorption process. Our findings have brought MgH2 a few steps closer to practical applications.

Mg‐MOF‐74 Derived Defective Framework for Hydrogen Storage at Above‐Ambient Temperature Assisted by Pt Catalyst

“…Interestingly, the H 2 uptake of de-MgMOF jumps to 1.6 wt.% when the adsorption and desorption temperatures increase to 200 and 300 °C, respectively. This phenomenon indicates that de-MgMOF has typical chemisorption characteristics, similar to the hydrogen absorption/desorption processes of nano-sized Mg. [17] To reduce the operation temperature, we applied a hydrogen spillover catalyst of Pt on de-MgMOF (denoted as Pt-de-MgMOF). Pt is in the forms of single atoms and clusters as observed by high-angular annular dark-field scanning transmission electron microscopy (HAADF-STEM, Figure S12, Supporting Information), with content of only 0.35 wt.% in Pt-de-MgMOF as measured by inductively coupled plasma optical emission spectrometer (ICP-OES, Table S1, Supporting Information).…”

Enhanced hydrogen storage property of MgH2 caused by a BaCrO4 nanocatalyst

“…MgO-, Fe- and Ba-based substances achieved heterogeneous catalytic effects on MgH 2 , thereby ameliorating the hydrogen storage performance. Chen et al 42 prepared BaTiO 3 to catalytically modify MgH 2 , and MgH 2 -20 wt% BaTiO 3 could fully discharge 6.0 wt% H 2 within 20 min at 310 °C. the E a value of the composite decreased to 60 kJ mol −1 in contrast to that of pure MgH 2 (101 kJ mol −1 ).…”