Engineering Spin States of Isolated Copper Species in a Metal-Organic Framework Improves Urea Electrosynthesis

作     者：Yuhang Gao Jingnan Wang Yijun Yang Jian Wang Chuang Zhang Xi Wang Jiannian Yao Yuhang Gao;Jingnan Wang;Yijun Yang;Jian Wang;Chuang Zhang;Xi Wang;Jiannian Yao

作者机构：Key Laboratory of PhotochemistryBeijing National Laboratory for Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190People’s Republic of China University of Chinese Academy of SciencesBeijing 100049People’s Republic of China Molecular Plus and Collaborative Innovation Center of Chemical Science and EngineeringTianjin UniversityTianjin 300072People’s Republic of China Department of PhysicsSchool of Physical Science and EngineeringBeijing Jiaotong UniversityBeijing 100044People’s Republic of China Research Center for Magnetic and Spintronic Materials National Institute for Materials ScienceTsukuba 305-0047Japan 

出 版 物：《Nano-Micro Letters》 (纳微快报（英文版）)

年 卷 期：2023年第15卷第9期

页      面：536-549页

核心收录：

学科分类：081702[工学-化学工艺] 08[工学] 0817[工学-化学工程与技术] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 0702[理学-物理学] 

基　　金：supported by“Key Program for International S&T Cooperation Projects of China”from the Ministry of Science and Technology of China(Grant No.2019YFE0123000) the National Natural Science Foundation of China(Grant Nos.91961125 and 21905019) Science and Technology Project of Guangdong Province(No.2020B0101370001) Chemistry and Chemical Engineering Guangdong Laboratory(No.1932004) the Project from China Petrochemical Corporation(No.S20L00151). 

主　　题：Electrocatalysis Urea synthesis Metal-organic framework Spin catalysis C-N coupling 

摘      要：The catalytic activities are generally believed to be relevant to the electronic states of their active center, but understanding this relationship is usually difficult. Here, we design two types of catalysts for electrocatalytic urea via a coordination strategy in a metal–organic frameworks: Cu^(Ⅲ)-HHTP and Cu^(Ⅱ)-HHTP. Cu^(Ⅲ)-HHTP exhibits an improved urea production rate of 7.78 mmol h^(−1)g^(−1) and an enhanced Faradaic efficiency of 23.09% at-0.6 V vs. reversible hydrogen electrode, in sharp contrast to Cu^(Ⅱ)-HHTP.Isolated CuⅢspecies with S = 0 spin ground state are demonstrated as the active center in Cu^(Ⅲ)-HHTP, different from Cu^(Ⅱ) with S = 1/2 in Cu^(Ⅱ)-HHTP. We further demonstrate that isolated Cu^(Ⅲ)with an empty dx2-y20orbital in Cu^(Ⅲ)-HHTP experiences a single-electron migration path with a lower energy barrier in the C–N coupling process, while Cu^(Ⅱ)with a single-spin state( d_(x2-y2)^(1)) in Cu^(Ⅱ)-HHTP undergoes a two-electron migration pathway.