Potential-Driven Coordinated Oxygen Migration in an Electrocatalyst for Sustainable H₂O₂ Synthesis

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Local coordination environment (LCE) manipulation is key for tuning nanomaterial electrocatalysis.
• Identifying active sites and understanding dynamic changes in electrocatalysts remain challenging.

Purpose of the Study:

• To investigate the influence of LCE on electrochemical H2O2 production using Pd clusters.
• To elucidate the role of sulfur and oxygen in the coordination environment on catalyst performance.

Main Methods:

• Density functional theory (DFT) calculations to screen catalyst designs.
• Synthesis of a Pd cluster catalyst (Pd/HMCS).
• Electrochemical evaluation in a flow cell and in situ characterizations.

Main Results:

• DFT identified the crucial role of first- and second-coordinated sulfur and oxygen in modulating HOO* binding.
• The Pd/HMCS catalyst achieved high mass activity (4.06 A mg⁻¹) and selectivity (>94%) for H2O2 production.
• A production rate of 16.3 mol gcat⁻¹ h⁻¹ was demonstrated in flow cell tests.

Conclusions:

• Optimized LCE, particularly involving sulfur and oxygen, significantly enhances Pd cluster electrocatalysis for H2O2 production.
• In situ observations revealed dynamic oxygen migration from the second to the first coordination sphere during operation.
• The synergistic effect of optimized LCE and dynamic oxygen migration leads to superior catalytic performance.