Bioinspired Tetranuclear Manganese Cubane Complex as an Efficient Molecular Electrocatalyst for Two‐Electron Water Oxidation Towards Hydrogen Peroxide

Abstract

AbstractStable homogeneous two‐electron water oxidation electrocatalysts are highly demanded to understand the precise mechanism and reaction intermediates of electrochemical H2O2 production. Here we report a tetranuclear manganese complex with a cubane structure which can electrocatalyze water oxidation to hydrogen peroxide under alkaline and neutral conditions. Such a complex demonstrates an optimal Faradaic efficiency (FE) of 87 %, which is amongst (if not) the highest FE(H2O2) of reported homogeneous and heterogeneous electrocatalysts. In addition, active species were identified and co‐catalysts were excluded through ESI‐MS characterization. Furthermore, we identified water binding sites and isolated one‐electron oxidation intermediate by chemical oxidation of the catalyst in the presence of water substrates. It is evident that efficient proton‐accepting electrolytes avoid rapid proton building‐up at electrode and substantially improve reaction rate and selectivity. Accordingly, we propose a two‐electron catalytic cycle model for water oxidation to hydrogen peroxide with the bioinspired molecular electrocatalyst. The present work is expected to provide an ideal platform to elucidate the two‐electron WOR mechanism at the atomic level.