Microscopic Scaling Relation of Ti-Based Catalysts in De/Hydrogenation Reactions of Mg/MgH2

作者：Haotian Guan, Yangfan Lu, Jiang Liu, Yuchuan Ye, Qian Li, Fusheng Pan · 发表于：ACS Catalysis · 年份：2024 · DOI：10.1021/acscatal.4c06122 · 被引用次数：53 · 研究领域：Hydrogen Storage and Materials、Ammonia Synthesis and Nitrogen Reduction、Advanced Chemical Physics Studies

While some early transition metals, such as Ti, can efficiently adsorb and dissociate hydrogen, they have rarely been utilized in hydrogenation and dehydrogenation (de/hydrogenation) reactions because their strong Cat–H bond results in a high hydrogen diffusion barrier. This limitation is known as the macroscopic scaling relation. Herein, using de/hydrogenation reactions of Mg/MgH 2 as the example, we report that the hydrogen dissociation and diffusion barrier can be scaled by the Ti valence state, leading to the establishment of a “microscopic” scaling relation. The reaction rates of Ti TM -MgO/MgH 2 are improved by 69–72 times compared to that of MgH 2 under the same conditions, which are even 10 times higher than those of Pd- and Pt-based catalysts. Kinetic analyses and density functional theory (DFT) calculations confirm that the electron transfer properties between catalysts and hydrogens can be systematically controlled as a function of Ti valence states, optimizing the Ti–H bond stability. Significantly, the chemical and structural properties of the Ti TM -MgO catalyst remained largely unchanged during and after de/hydrogenation reactions. Our results revealed a “microscopic” scaling relation within a single element governed by its valence state, offering a blueprint for the application of early transition metals in de/hydrogenation reactions.