Enhanced reactive oxygen species generation: Synergic process of three-electron oxygen reduction and electrochemical ozone production by bimetallic La-Nb oxides

Abstract

The anodic electrochemical ozone production (EOP) and the cathodic three-electron oxygen reduction reaction (3e⁻ ORR) are effective processes for generating active oxygen species (ROS). However, the activation of ozone (O₃) by hydroxyl radical (·OH) to form ROS poses significant challenges. The micelle ball-like bimetallic La-Nb oxides (LNOx) have been developed as a bifunctional electrocatalyst for both the EOP and 3e⁻ ORR reactions. The LNO20 demonstrated a 9.8% of Faradaic efficiency (FE) in O₃ production and a transfer number of 2.8 electrons in the 3e⁻ ORR. Theoretical calculations support the notion that the five-membered ring mechanism in LNO20 facilitates O₃ production. Additionally, the incorporation of La provides active sites that enhance the activation of hydrogen peroxide (*H₂O₂) and the generation of ·OH. This innovative approach synergistically integrates EOP and 3e⁻ ORR, enhancing the activation of O₃ to produce ROS, demonstrating exceptional efficacy in the degradation of organic pollutants and antimicrobial activity. The study paves the way for designing advanced electrocatalysts for EOP and 3e⁻ ORR and offers insights into utilizing electrochemical method to support other antibacterial strategies.