A Trade‐Off Between Thermodynamics and Kinetics of O <sub>2</sub> Binding for Highly Active and Selective Electrocatalytic Oxygen Reduction Reaction
Abstract
ABSTRACT O 2 binding to metal ions is an essential step in the oxygen reduction reaction (ORR). Tailoring O 2 binding is anticipated to realize highly active and selective four‐electron ORR. Herein, we report on fine‐tuning the molecular pocket of Co porphyrins to get a trade‐off between thermodynamics and kinetics of O 2 binding for ORR with high activity and selectivity. Three Co tetra (2‐amidophenyl)porphyrins with an αααα structure but different steric hindrance at the pocket bottleneck are synthesized. The pocket thermodynamically favors O 2 binding by stabilizing O 2 adducts and thus improves the 4e selectivity, but the sterically hindered pocket entrance may obstruct the access of O 2 to Co. By tuning the pocket entrance, we tailored the rate constant and equilibrium constant of O 2 binding, and consequently, we achieved efficient ORR with a half‐wave potential of 0.83 V versus RHE and a transferred electron number of 3.78. This performance is remarkable among reported mononuclear Co porphyrins.
Article Details
Authors (13)
Haoyuan Lv
Jianqiang Feng
Institute of Molecular Engineering Plus, College of Chemistry, Fuzhou University 2 , Fuzhou 350108,
Haonan Qin
Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering
Jiwu Zhao
State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry
Qiqi Jing
Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education School of Chemistry and Chemical Engineering Shaanxi Normal University Xi'an China
Tao Liu
Yuhan Xu
Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering
Jinxiu Han
Key Laboratory of Applied Surface and Colloid Chemistry Ministry of Education School of Chemistry and Chemical Engineering Shaanxi Normal University Xi'an China
Wei Zhang
Ping Yang
Binju Wang
State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering
Ulf‐Peter Apfel
Ruhr‐Universität Bochum Fakultät Für Chemie und Biochemie Anorganische Chemie I Bochum Germany
Rui Cao
Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering