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Efficient Homogeneous Electrocatalytic Water Oxidation by a Manganese Cluster with an Overpotential of Only 74 mV
Author(s) -
Ghosh Totan,
Maayan Galia
Publication year - 2019
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201813895
Subject(s) - overpotential , electrocatalyst , manganese , electrolysis of water , oxygen evolution , catalysis , electrochemistry , chemistry , inorganic chemistry , electrolysis , water splitting , photosystem ii , redox , cluster (spacecraft) , photosynthesis , electrode , photocatalysis , organic chemistry , biochemistry , computer science , electrolyte , programming language
Water electrolysis is among the simplest method for generating hydrogen as an alternative renewable fuel. A major challenge associated with this process is the development of cheap, simple, and environmentally benign catalysts that lead to a minimum overpotential for water oxidation. Inspired by the Mn 4 CaO x cluster that catalyzes water oxidation in photosystem II, described here is the synthesis and characterization of the manganese cluster [Mn 12 O 12 (O 2 CC 6 H 2 (OH) 3 ) 16 (H 2 O) 4 ] (Mn 12 TH) along with its electrocatalytic activity at pH 6. Electrochemical, spectroscopic, and electron microscopy studies show that Mn 12 TH is a homogeneous electrocatalyst for water oxidation and enables oxygen evolution with a reaction rate of 22 s −1 , high Faradic efficiency (93 %), and an overpotential of only 74 mV, the lowest reported to date. Based on the electrochemical data, the organic ligands, which can be described as the second coordination sphere of the catalytic manganese core, play a key role in facilitating the oxidation process and accelerating the reaction.