Phosphorus-Induced Electron Pump Enhances O₂ Activation for Electrocatalytic H₂O₂ Production

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical two-electron oxygen reduction reaction (2e- ORR) to produce hydrogen peroxide (H2O2) is desirable but limited by poor selectivity and activity.
• Developing efficient catalysts for selective H2O2 production remains a significant challenge in electrochemistry.

Purpose of the Study:

• To demonstrate a phosphorus-induced electron pump for enhancing the electrochemical 2e- ORR.
• To investigate the mechanism of oxygen activation and intermediate formation during the 2e- ORR.
• To explore the potential applications of the developed system, such as pollutant degradation.

Main Methods:

• Fabrication and characterization of a phosphorus-induced electron pump catalyst.
• Electrochemical measurements, including cyclic voltammetry and chronoamperometry, to evaluate ORR performance.
• In situ Raman spectroscopy and density functional theory (DFT) calculations to elucidate reaction mechanisms.
• Assessment of the catalyst's efficacy in degrading antibiotics and Escherichia coli.

Main Results:

• The phosphorus-induced electron pump achieved >90% H2O2 selectivity (93.5% at 0.5 V) within the 0.2–0.7 V potential range.
• A high Faradaic efficiency of 94.2% for H2O2 production was observed at 0.6 V.
• In situ Raman and DFT calculations revealed enhanced O2 adsorption/activation and earlier formation of *OOH intermediates.
• The system demonstrated potential for on-site degradation of antibiotics and Escherichia coli.

Conclusions:

• The phosphorus-induced electron pump effectively enhances electrocatalytic 2e- ORR, offering high H2O2 selectivity and activity.
• The study provides mechanistic insights into oxygen activation and intermediate stabilization, extending the understanding of electron pump mechanisms.
• The demonstrated application in pollutant degradation highlights the practical potential of this electrocatalytic system.