Molecule Confined Isolated Metal Sites Enable the Electrocatalytic Synthesis of Hydrogen Peroxide. Issue 25 (19th September 2021)

• Record Type: Journal Article
• Authors: Li, Xiaogang; Tang, Shasha; Dou, Shuo; Fan, Hong Jin; Choksi, Tej S.; Wang, Xin
• Is Part Of: Advanced materials. Volume 34:Issue 25(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-09-19
• Subjects: electrocatalysis -- hydrogen peroxide -- isolated metal sites -- molecular confinement -- oxygen reduction; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202104891
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: The direct synthesis of hydrogen peroxide (H2 O2 ) through the two‐electron oxygen reduction reaction is a promising alternative to the industrial anthraquinone oxidation process. Selectivity to H2 O2 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 H2 O2 through the two‐electron pathway. Confining isolated NiN x sites under aminoanthraquinone increases the selectivity to H2 O2 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 H2 O2 . It is revealed how tailoring noncovalent interactions beyond the binding site can empower electrocatalysts for the direct synthesis of H2 O2 through oxygen reduction. Abstract : Aminoanthraquinone confined on isolated NiN x sites effectively modulates the electrocatalytic oxygen reduction reaction toward hydrogen peroxide (H2 O2 ) production. The NiN x sites favor oxygen reduction to OOH*. Confinement effects created by the molecule on NiN x sites promote OOH* desorption to H2 O2 . The molecularly confined catalyst achieves the high selectivity above 80% for H2 O2 with a small overpotential.