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Unpaired 3d Electrons on Atomically Dispersed Cobalt Centres in Coordination Polymers Regulate both Oxygen Reduction Reaction (ORR) Activity and Selectivity for Use in Zinc–Air Batteries
Author(s) -
Lian Yuebin,
Yang Wenjuan,
Zhang Chufeng,
Sun Hao,
Deng Zhao,
Xu Wenjie,
Song Li,
Ouyang Zhongwen,
Wang Zhenxing,
Guo Jun,
Peng Yang
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201910879
Subject(s) - bimetallic strip , cobalt , unpaired electron , catalysis , chemistry , crystallinity , oxygen reduction , ligand (biochemistry) , transition metal , selectivity , metal , oxygen , electrocatalyst , zinc , oxygen reduction reaction , inorganic chemistry , photochemistry , materials science , crystallography , electrode , electrochemistry , radical , organic chemistry , biochemistry , receptor
Reversible oxygen conversion is important for various green energy technologies. Herein we synthesize a series of bimetallic coordination polymers by varying the Ni/Co ratio and using HITP (HITP=2,3,6,7,10,11‐hexaiminotriphenylene) as the ligand, to interrogate the role of metal centres in modulating the activity of the oxygen reduction reaction (ORR). Co 3 HITP 2 and Ni 3 HITP 2 are compared. Unpaired 3d electrons in Co 3 HITP 2 result in less coplanarity but more radical character. Thus, despite of a reduced crystallinity and conductivity, the best ORR activity, comparable to 20 % Pt/C, is obtained for Co 3 HITP 2 , showing the 3d orbital configuration of the metal centre promotes ORR. Experimental and DFT studies show a transition of ORR pathway from four‐electron for Co 3 HITP 2 to two‐electron for Ni 3 HITP 2 . Rechargeable zinc–air batteries using Co 3 HITP 2 as the air cathode catalyst demonstrate excellent energy efficiency and stability.