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Reversible Ligand Exchange in Atomically Dispersed Catalysts for Modulating the Activity and Selectivity of the Oxygen Reduction Reaction
Author(s) -
Kim Jae Hyung,
Shin Dongyup,
Kim Jinjong,
Lim June Sung,
Paidi Vinod K.,
Shin Tae Joo,
Jeong Hu Young,
Lee KugSeung,
Kim Hyungjun,
Joo Sang Hoon
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202108439
Subject(s) - catalysis , selectivity , chemistry , reactivity (psychology) , ligand (biochemistry) , redox , oxidation state , oxygen , oxygen reduction reaction , metal , inorganic chemistry , photochemistry , combinatorial chemistry , electrochemistry , organic chemistry , electrode , receptor , biochemistry , medicine , alternative medicine , pathology
Rational control of the coordination environment of atomically dispersed catalysts is pivotal to achieve desirable catalytic reactivity. We report the reversible control of coordination structure in atomically dispersed electrocatalysts via ligand exchange reactions to reversibly modulate their reactivity for oxygen reduction reaction (ORR). The CO‐ligated atomically dispersed Rh catalyst exhibited ca. 30‐fold higher ORR activity than the NH x ‐ligated catalyst, whereas the latter showed three times higher H 2 O 2 selectivity than the former. Post‐treatments of the catalysts with CO or NH 3 allowed the reversible exchange of CO and NH x ligands, which reversibly tuned oxidation state of metal centers and their ORR activity and selectivity. DFT calculations revealed that more reduced oxidation state of CO‐ligated Rh site could further stabilize the *OOH intermediate, facilitating the two‐ and four‐electron pathway ORR. The reversible ligand exchange reactions were generalized to Ir‐ and Pt‐based catalysts.