Highly Active and Renewable Catalytic Electrodes for Two-Electron Oxygen Reduction Reaction

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Hydrogen peroxide (H2O2) is a vital chemical with diverse applications.
• Current H2O2 production methods are energy-intensive and environmentally concerning.
• Developing efficient and sustainable H2O2 synthesis routes is a significant scientific challenge.

Purpose of the Study:

• To investigate antimony-doped tin oxide (ATO) as a renewable catalyst for electrochemical H2O2 synthesis.
• To understand the role of antimony doping on the electrocatalytic activity for the two-electron oxygen reduction reaction (2e-ORR).
• To elucidate the mechanism behind the enhanced activity and selectivity of ATO.

Main Methods:

• Synthesis and characterization of antimony-doped tin oxide (ATO) materials.
• Electrochemical evaluation using a three-electrode cell setup.
• Density functional theory (DFT) simulations to model catalytic mechanisms.

Main Results:

• ATO exhibits remarkable electrocatalytic activity for the 2e-ORR, with activity showing a volcano-type relationship with antimony doping levels.
• DFT simulations revealed that isolated Sb atoms enhance O2 adsorption and reduce activation energy for 2e-ORR.
• Stable H2O2 production with a turnover frequency of 6.6 s-1 was achieved using ATO (10.2 mol % Sb) at -0.22 V vs RHE.
• The catalyst's activity remained high even after surface sputtering, indicating robust performance.

Conclusions:

• Antimony-doped tin oxide is a highly effective and renewable catalyst for the electrochemical synthesis of H2O2.
• The isolated Sb atom plays a crucial role in the superior performance of ATO for 2e-ORR.
• ATO offers a promising pathway for sustainable and efficient H2O2 production.