Molecule Confined Isolated Metal Sites Enable the Electrocatalytic Synthesis of Hydrogen Peroxide
Xiaogang Li, Shasha Tang, Shuo Dou, Hong Jin Fan, Tej S. Choksi, Xin Wang
Abstract
Abstract The direct synthesis of hydrogen peroxide (H 2 O 2 ) through the two‐electron oxygen reduction reaction is a promising alternative to the industrial anthraquinone oxidation process. Selectivity to H 2 O 2 is however limited by the four‐electron pathway during oxygen reduction. Herein, it is reported that aminoanthraquinone confined isolated metal sites on carbon supports selectively steer oxygen reduction to H 2 O 2 through the two‐electron pathway. Confining isolated NiN x sites under aminoanthraquinone increases the selectivity to H 2 O 2 from below 55% to above 80% over a wide potential range. Spectroscopy characterization and density functional theory calculations indicate that isolated NiN x sites are confined within a nanochannel formed between the molecule and the carbon support. The confinement reduces the thermodynamic barrier for OOH* desorption versus further dissociation, thus increasing the selectivity to H 2 O 2 . It is revealed how tailoring noncovalent interactions beyond the binding site can empower electrocatalysts for the direct synthesis of H 2 O 2 through oxygen reduction.