Self-Growing MZIF8/GDE Bonding by N–Zn–O Boosts Electrochemical Oxygen Reduction to H2O2

Abstract

The two-electron oxygen reduction reaction (2e– ORR) is an environmentally friendly approach to the production of H2O2. Self-growing gas diffusion electrodes offer a lot of advantages like reduction of adhesive use, and lower electron and mass transfer resistance. However, MOF self-growing gas diffusion electrodes are rarely used for the production of hydrogen peroxide. Herein, a self-growing hydrophobic composite gas diffusion electrode has been proposed, consisting of densely distributed MZIF8 and graphite felt support (MGF). MGF performs well in a wide range of pH and potential; the H2O2 yields in 0.5 M Na2SO4 and 0.1 M KOH are 980.86 and 981.74 mg·L–1·h–1, respectively. In addition, the highest Faraday efficiencies achieved by MGF in the two solutions are 85.75% and 89.88%, respectively. This significant performance is attributed to the hydrophobic microenvironment and the ordered distribution of the N–Zn–O bond located between the MZIF8 and graphite felt support. This work presents a promising method for the production of H2O2 with high selectivity, simple preparation, low cost, and wider application.