Mimicking Metalloenzyme Microenvironments in the Transition Metal-Single Atom Catalysts for Electrochemical Hydrogen Peroxide Synthesis in an Acidic Medium

Saravanakumar Muthusamy, Palani Sabhapathy, Putikam Raghunath, Amr Sabbah, Yu Chung Chang, Vimal Krishnamoorthy, Thi Thong Ho, Jau Wern Chiou, Ming Chang Lin, Li Chyong Chen*, Kuei Hsien Chen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Electrochemical reduction of oxygen into hydrogen peroxide in an acidic medium offers an energy-efficient and green H2O2 synthesis as an alternative to the energy-intensive anthraquinone process. Unfortunately, high overpotential, low production rates, and fierce competition from traditional four-electron reduction limit it. In this study, a metalloenzyme-like active structure is mimicked in carbon-based single-atom electrocatalysts for oxygen reduction to H2O2. Using a carbonization strategy, the primary electronic structure of the metal center with nitrogen and oxygen coordination is modulated, followed by epoxy oxygen functionalities close to the metal active sites. In an acidic medium, CoNOC active structures proceed with greater than 98% H2O2 selectivity (2e/2H+) rather than CoNC active sites that are selective to H2O (4e/4H+). Among all MNOC (M = Fe, Co, Mn, and Ni) single-atom electrocatalysts, the CoNOC is the most selective (> 98%) for H2O2 production, with a mass activity of 10 A g−1 at 0.60 V vs. RHE. X-ray absorption spectroscopy is used to identify the formation of unsymmetrical MNOC active structures. Experimental results are also compared to density functional theory calculations, which revealed that the structure-activity relationship of the epoxy-surrounded CoNOC active structure reaches optimum (ΔG*OOH) binding energies for high selectivity.

Original languageEnglish
Article number2300234
JournalSmall Methods
Volume7
Issue number10
DOIs
StatePublished - 20 Oct 2023

Keywords

  • d-band center
  • electrocatalysis
  • electrochemical HO production
  • electronic structures
  • oxygen reduction reaction
  • single-atom catalysts

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