Simultaneous ozone and hydrogen peroxide electrosynthesis via defect modulation in Ni, Sb‐doped SnO₂ electrocatalysts

Abstract

Electrochemical synthesis of green oxidants O3 and H2O2 is valuable for applications, but challenges persist in enhancing the O3 and H2O2 generation activity and combined application. Herein, we modulate the surface Ni active sites and oxygen vacancy defects content in Ni‐Sb‐SnO2 electrocatalysts to enhance selectivity for electrochemical ozone generation (EOP) and two‐electron electrochemical oxygen reduction reactions (2e− ORR). The Ni active sites and oxygen vacancy defects enriched electrocatalysts resulting in an ozone faradaic efficiency of 48.1%, while non‐enriched electrocatalyst obtained 90% selectivity for H2O2. Theoretical calculations revealed that Ni‐Sb‐SnO2 efficiently captures O2 with defective Ovac2 stabilize intermediates, facilitating O3 and H2O2 synthesis. Moreover, concerted EOP and 2e− ORR enable concurrent generation of O3 and H2O2 for efficient synergistic degradation of organic pollutants, while attenuating the energy demands of the electrolyzer. This study provides an appealing strategy for simultaneous production of O3 and H2O2 with applications in wastewater treatment.

Interplay between Catalyst Corrosion and Homogeneous Reactive Oxygen Species in Electrochemical Ozone Production

“…Our group showed that increasing the thickness of NATO electrodes increased both reaction activity and selectivity, which cannot be explained without invoking transport of solution-phase intermediates . Work by Ding et al and Zhang et al revealed that NATO catalysts generate hydroxyl radicals ( • OH). , Lansing et al showed that quenching • OH had a minimal effect on EOP from NATO electrodes, while quenching hydroperoxyl radicals ( • OOH) significantly decreased it . These findings diverge from the conventional perspectives of both AEM and LOM, which typically assume the involvement of only surface-adsorbed intermediates.…”

“…Figure 5 A shows that both NATO (EOP active) and ATO (EOP inactive) generate • OH at 2.70 V, consistent with the literature. 7 , 43 , 44 , 77 • OH radicals were detected via their selective reaction with benzoic acid to generate hydroxybenzoic acids. Importantly, benzoic acid should be selective to • OH because the presence of the carboxylic group in benzoic acid deactivates the electrophilic substitution reaction by O 3 .…”

“… 28 Work by Ding et al and Zhang et al revealed that NATO catalysts generate hydroxyl radicals ( • OH). 43 , 44 Lansing et al showed that quenching • OH had a minimal effect on EOP from NATO electrodes, while quenching hydroperoxyl radicals ( • OOH) significantly decreased it. 32 These findings diverge from the conventional perspectives of both AEM and LOM, which typically assume the involvement of only surface-adsorbed intermediates.…”

A Co-Doping Materials Design Strategy for Selective Ozone Electrocatalysts

“…Among these methods, six-electron electrochemical ozone production (EOP) holds significant potential. Ozone (O 3 ) is a potent oxidizer with a lower environmental impact than traditional disinfectants, and it can be generated on site through EOP. − Furthermore, EOP produces hydrogen as a byproduct, potentially enhancing the cost-effectiveness of water treatment .25ex2ex 3 H 2 O → O 3 + 6 H + + 6 e − ⁣ E ◦ = 1.51 V vs RHE .25ex2ex 2 H 2 O → O 2 + 4 H + + 4 e − ⁣ E ◦ = 1.23 V vs RHE …”

“…Ozone (O 3 ) is a potent oxidizer with a lower environmental impact than traditional disinfectants, and it can be generated on site through EOP. 2 − 5 Furthermore, EOP produces hydrogen as a byproduct, potentially enhancing the cost-effectiveness of water treatment. 6 …”