Isegawa Miho, Matsumoto Takahiro, Ogo Seiji
International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University 744 Moto-oka, Nishi-ku Fukuoka 819-0395 Japan
RSC Adv. 2021 Aug 23;11(45):28420-28432. doi: 10.1039/d1ra05928a. eCollection 2021 Aug 16.
Hydrogen is a clean fuel alternative to fossil fuels, and it is vital to develop catalysts for its efficient activation and production. We investigate the reaction mechanism of H activation in an aqueous solution by the recently developed NiFe complex (Ogo . 2020, 6, eaaz8181) using density functional theory (DFT) calculation. Our computational results showed that H is activated using frustrated Lewis pair. That is, H binds to the Fe site of the NiFe complex, acting as a Lewis acid, while the added buffer, acting as Lewis base, abstracts protons to form a hydride complex. Furthermore, the higher basicity in the proton abstraction reaction characterises reaction more exergonic and lowers the reaction barrier. In addition, in the proton abstraction by the water molecule, the reaction barrier was lowered when anion such as Cl is in the vicinity of the water. Understanding the chemical species that contribute to the catalytic process in cooperation with the metal catalyst at the atomic level should help to maximise the function of the catalyst.
氢是一种可替代化石燃料的清洁燃料，开发用于其高效活化和生产的催化剂至关重要。我们使用密度泛函理论（DFT）计算，通过最近开发的NiFe配合物（Ogo. 2020, 6, eaaz8181）研究了水溶液中氢活化的反应机理。我们的计算结果表明，氢是通过受阻路易斯酸碱对进行活化的。也就是说，氢与NiFe配合物的铁位点结合，充当路易斯酸，而添加的缓冲剂充当路易斯碱，夺取质子形成氢化物配合物。此外，质子夺取反应中较高的碱度使反应更具放能性，并降低了反应势垒。另外，在水分子夺取质子的过程中，当诸如Cl等阴离子在水附近时，反应势垒会降低。在原子水平上理解与金属催化剂协同作用于催化过程的化学物种，应有助于使催化剂的功能最大化。
