Synchronous generation of green oxidants H2O2 and O3 by using a heterojunction bifunctional ZnO/ZnS@C electrocatalyst

Abstract

H₂O₂ and O₃ production through electrochemical synthesis is a promising approach to replace anthraquinone processes and corona discharge. However, the simultaneous generation of H₂O₂ and O₃ and the use of their synergistic oxidation to degrade organic contaminants remains a challenge. Herein, heterojunction bifunctional ZnO/ZnS@C electrocatalysts were prepared by a one-step pyrolysis method. ZnO/ZnS@C-750 can achieve 90% selectivity for H₂O₂ and 11% Faraday efficiency for gaseous O₃. The primary contributor to such a performance was exploited to accelerate the electron transfer on the heterogeneous interface and generate more reaction sites. H₂O₂ and O₃ can also be simultaneously generated in the electrolyzer and the synergistic effect of H₂O₂ and O₃ can be utilized to completely degrade organic pollutants, such as phenol and tetracycline. This work provided new insights into the design of the 2e⁻ ORR (oxygen reduction reaction) and EOP (electrochemical ozone production) bifunctional electrocatalysts for pollutant degradation.