Molecule confined isolated metal sites enable the electrocatalytic synthesis of hydrogen peroxide

• Main Authors: Li, Xiaogang, Tang, Shasha, Dou, Shuo, Fan, Hong Jin, Choksi, Tej S., Wang, Xin
• Other Authors: School of Chemical and Biomedical Engineering
• Format: Article
• Language: English
• Published: 2022
• Subjects: Engineering::Chemical engineering; Electrocatalysis; Hydrogen Peroxide
• Online Access: https://hdl.handle.net/10356/160708
• Institution: Nanyang Technological University

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 NiNx 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 NiNx 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.