Mesoporous MnO_(2)nanosheets for efficient electrocatalytic nitrogen reduction via high spin polarization induced by oxygen vacancy  

作　　者：Yangyang Wen Jiahao Liu Feiran Zhang Zhenxing Li Ping Wang Zhao Fang Miao He Jingshuai Chen Weiyu Song Rui Si Lianzhou Wang 

机构地区：[1]State Key Laboratory of Heavy Oil Processing,College of New Energy and Materials,China University of Petroleum(Beijing),Beijing 102249,China [2]College of Science,China University of Petroleum(Beijing),Beijing 102249,China [3]School of Chemistry and Chemical Engineering,Anhui University,Hefei 230601,China [4]Shanghai Synchrotron Radiation Facility,Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201204,China [5]Nanomaterials Centre,School of Chemical Engineering and Australian Institute for Bioengineering and Nanotechnology,The University of Queensland,Brisbane,QLD 4072,Australia

出　　处：《Nano Research》2023年第4期4664-4670,共7页纳米研究（英文版）

基　　金：financial support from the National Nature Science Foundation of China(No.22122113);National Key Research and Development Program of China(No.2021YFB4000405).

摘　　要：The electrochemical N_(2)reduction reaction(NRR)represents a green and sustainable route for NH_(3)synthesis under ambient conditions.However,the mechanism of N_(2)activation in the electrocatalytic NRR remains unclear.Herein,we found that the high spin state Mn^(3+)-Mn^(3+)pairs induced by oxygen vacancy in MnO_(2)nanosheets greatly enhance the catalytic activities.The strong electron transfer between d orbital of Mn and orbital of N2 forces the N_(2)to be of radical nature,which activates the hydrogenation process and weakens the N≡N bond.Based on the density functional theory(DFT)calculation results,we precisely designed mesoporous MnO_(2)nanosheets with rich oxygen vacancies via using methyltriphenylphosphonium bromide(MPB)to induce more Mn^(3+)-Mn^(3+)pairs(Mn^(3-3)-MnO_(2)),which can achieve a fairly high ammonia yield of up to 147.2μg·h^(−1)·mgcat−1.at−0.75 V vs.reversible hydrogen electrode(RHE)and a high Faradaic efficiency(FE)of 11%.Furthermore,these mesoporous MnO_(2)nanosheets exhibit the superior durability with negligible changes in both NH3 yield and FE after a consecutive 6-recycle test and the current density electrolyzed over a 24-hour period.Our findings offer an approach to designing highly active transition metal catalysts for electrocatalytic nitrogen reduction.

关 键 词：Mn^(3+)-Mn^(3+)pair MnO_(2)nanosheets MESOPORES ammonia synthesis electrocatalytic nitrogen reduction 

分 类 号：O64[理学—物理化学]