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A Nickel(II) Complex as a Homogeneous Electrocatalyst for Water Oxidation at Neutral pH: Dual Role of HPO 4 2− in Catalysis
Author(s) -
Wang JiaWei,
Zhang XiangQiong,
Huang HaiHua,
Lu TongBu
Publication year - 2016
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201600796
Subject(s) - electrocatalyst , catalysis , chemistry , nickel , overpotential , inorganic chemistry , electron transfer , polyoxometalate , hydrogen peroxide , proton coupled electron transfer , photochemistry , homogeneous catalysis , water splitting , electrochemistry , photocatalysis , organic chemistry , electrode
A new mononuclear nickel complex, featuring two cis ‐relative labile sites, is reported as a homogeneous electrocatalyst for water oxidation in a neutral phosphate buffer. The water oxidation catalysis can be initiated at a moderate overpotential of approximately 0.48 V. Mechanistic studies reveal that the oxidation of water by a two‐electron oxidized species of the nickel catalyst is feasible, with formation of a peroxide intermediate through intramolecular O−O coupling. Interestingly, it has been found that the buffer base (HPO 4 2− ) plays a dual role in the catalytic system: it acts as a proton acceptor to expedite proton‐coupled electron transfer (PCET) during catalysis, but it also suppresses the electrocatalysis through an anation process.