A Unique Nanoflake‐Shape Bimetallic Ti–Nb Oxide of Superior Catalytic Effect for Hydrogen Storage of MgH2

MgH₂ is one of the most promising solid hydrogen storage materials due to its high capacity, excellent reversibility, and low cost. However, its operation temperature needs to be greatly reduced to realize its practical applications, especially in the highly desired fuel cell fields. This work synthesizes a 2D nanoflake-shape bimetallic Ti-Nb oxide of TiNb₂ O₇ , which has high surface area and shows superior catalytic effect for the hydrogen storage of MgH₂ . Incorporated with the TiNb₂ O₇ nanoflakes as low as 3 wt%, MgH₂ shows a low onset dehydrogenation temperature of 178 °C, which is lowered by 100 °C compared with the pristine one. A dehydrogenation capacity as high as 7.0 wt% H₂ is achieved upon heating to 300 °C. The capacity retention is as high as 96% after 30 cycles. The mechanism of the improved hydrogen storage properties is analyzed by density functional theory (DFT) calculation and the microstructural evolution during dehydrogenation and hydrogenation. This work provides an MgH₂ system with high available capacity and low operation temperature by a unique structural design of the catalyst. The high surface area feature of the TiNb₂ O₇ nanoflakes and the synthesis method hopefully can develop the application of TiNb₂ O₇ .