西南科技大学陈林团队报道了形成金属氢化物的质子隧穿距离决定电化学CO₂还原反应的选择性。相关研究成果于2023年3月15日发表在国际顶尖学术期刊《德国应用化学》。

制备了一系列锰多吡啶配合物作为CO₂还原电催化剂。在这些催化剂中，形成金属氢化物（PTD-MH）的分子内质子隧穿距离在2.400到2.696之间变化，而结构、能量和电子因素基本保持相近。实验和理论结果表明，CO₂还原反应（CO2RR）的选择性由分子内PTD-MH主导，差异约为0.3。

具体而言，用具有稍长PTD-MH的侧基酚官能化的催化剂更倾向于质子与[Mn-CO2]加合物的结合，而不是与Mn中心的结合，并导致约100%的CO产物选择性。相反，通过在相同的催化剂骨架中连接悬挂的叔胺来降低PTD-MH有助于质子与Mn中心的结合，并以86%的选择性将产物从CO转换为HCOOH。

附：英文原文

Title: Proton Tunneling Distances for Metal Hydrides Formation Manage the Selectivity of Electrochemical CO2 Reduction Reaction

Author: Shuanglin He, Yuhang Qing, Ping Zhang, Ying Xiong, Qianqian Wu, Yaping Zhang, Lin Chen, Fang Huang, Fei Li

Issue&Volume: 2023-03-15

Abstract: A series of manganese polypyridine complexes were prepared as CO2 reduction electrocatalysts. In these catalysts, the intramolecular proton tunneling distance for metal hydride formation (PTD-MH) vary from 2.400 to 2.696 while the structural, energetic and electronic factors remain essentially close. The experimental and theoretical results revealed that the selectivity of CO2 reduction reaction (CO2RR) is dominated by the intramolecular PTD-MH within a difference of ca. 0.3 in PTD-MH. Specifically, the catalyst functionalized with a pendent phenol group featuring a slightly longer PTD-MH prefers the binding of proton to the [Mn-CO2] adduct rather than the Mn center and results in ca. 100% selectivity for CO product. By contrast, decreasing the PTD-MH by attaching a dangling tertiary amine in the same catalyst skeleton facilitates the proton binding on the Mn center and switches the product from CO to HCOOH with a selectivity of 86%.

DOI: 10.1002/anie.202216082

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202216082