Hetero-N-Coordinated Co Single Sites with High Turnover Frequency for Efficient Electrocatalytic Oxygen Evolution in an Acidic Medium AITranslate

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DOI：https://doi.org/10.1021/acsenergylett.9b01129

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The development of noble-metal-free, acid-compatible oxygen electrocatalysts and monitoring their active sites’ evolution under working conditions are crucial for global renewable energy storage and conversion. Here, we present a new type of hetero-N-coordinated Co (HNC-Co) single sites, with Co active centers bonding to hetero pyridinic- and amino-N ligands, as an efficient oxygen evolution reaction (OER) electrocatalyst in an acidic medium. The atomically dispersed HNC-Co electrocatalyst could effectively oxidize water at a quite low overpotential of 265 mV at 10 mA cm–2 in 0.5 M H2SO4 solution with an ultrahigh turnover frequency of 2.8 s–1 and a huge mass activity of 7.6 A mg–1, ∼80–240 times that of commercial IrO2. By using operando synchrotron infrared spectroscopy, a potential-driven active site evolution of H2N–(*O–Co)–N4 is observed for the first time during the OER process, which greatly promotes the surface oxo-species transformation for efficient acidic OER catalysis.