Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871, Japan.
Elements Strategy Initiative for Catalysts Batteries ESICB, Kyoto University, Katsura, Kyoto, 615-8520, Japan.
Nat Commun. 2019 Sep 25;10(1):4094. doi: 10.1038/s41467-019-12018-7.
The hydrogen isotope deuterium is widely used in the synthesis of isotopically-labeled compounds and in the fabrication of semiconductors and optical fibers. However, the facile production of deuterium gas (D) and hydrogen deuteride (HD) in a controlled manner is a challenging task, and rational heterogeneously-catalyzed protocols are still lacking. Herein, we demonstrate the selective production of hydrogen isotope compounds from a combination of formic acid and DO, through cooperative action by a PdAg nanocatalyst on a silica substrate whose surface is modified with amine groups. In this process, D is predominantly evolved by the assist of weakly basic amine moieties, while nanocatalyst particles in the vicinity of strongly basic amine groups promote the preferential formation of HD. Kinetic data and calculations based on semi-classically corrected transition state theory coupled with density functional theory suggest that quantum tunneling dominates the hydrogen/deuterium exchange reaction over the metallic PdAg surfaces.
氘（氢的同位素）被广泛应用于同位素标记化合物的合成和半导体及光纤的制造。然而，以可控的方式制备氘气（D）和氘化氢（HD）是一项具有挑战性的任务，合理的多相催化方案仍然缺乏。在此，我们展示了通过负载在氨基功能化二氧化硅基底上的钯银纳米催化剂的协同作用，从甲酸和 DO 的混合物中选择性地制备氢同位素化合物。在这个过程中，弱碱性的氨基基团促进了 D 的主要生成，而强碱性的氨基基团附近的纳米催化剂颗粒则促进了 HD 的优先形成。基于半经典校正过渡态理论与密度泛函理论相结合的动力学数据和计算表明，量子隧道效应主导了 PdAg 金属表面上的氢/氘交换反应。
