Facet‐Engineered Anatase TiO <sub>2</sub> Nanoflowers with Anchored Single‐Atom Pd for Ultrafast Hydrogen Storage Kinetics
Qingyun Shi, Risheng Bai, Chunmin Zhang, Pai Huang, Jiale Li, Chunli Wang, Jianguang Yuan, Ying Wang, Dongming Yin, Limin Wang, Han Zhu, Yong Cheng
Abstract
Abstract Securing a clean and sustainable energy future hinges on developing high‐performance hydrogen storage technologies. However, the widely practical application is hindered by slow kinetics and high thermodynamic stability. Herein, a facet‐engineered strategy is developed to modulate metal–support interactions by constructing marimo‐like anatase TiO 2 nanoflowers enriched with {001} facets as scaffolds for Pd single atoms (PdSAs/A‐TiO 2 ). Strong Pd–O bonding and nano‐confinement ensure atomic dispersion and electronic coupling. The MgH 2 ‐PdSAs/A‐TiO 2 composite exhibits ultrafast H 2 release (6 wt.% in 3.5 min at 250°C) and absorption (1.2 wt.% in 5 min at 25°C). PdSAs‐induced electronic modulation shifts Ti 3d states toward the Fermi level, enhancing hydrogen activation and reducing the energy barrier of rate‐determining step (RDS) in Mg/MgH 2 from 1.43 to 0.31 eV. A high capacity retention of 92.6% after 10 dehydrogenation/re‐hydrogenation cycles at 300°C is achieved by MgH 2 ‐PdSAs/A‐TiO 2 NFs, in sharp contrast to ball‐milled MgH 2 (46.1%). In situ formation of a MgTi 2 O 4 interfacial phase replaces the inert MgO layer, providing a fast hydrogen transport network that facilitates H‐atom migration between PdSAs and the Mg matrix. This facet‐directed single‐atom and interfacial phase engineering concept offers a unified strategy to overcome thermodynamic and kinetic bottlenecks in MgH 2 ‐based hydrogen storage.