A high throughput optical method for studying compositional effects in electrocatalysts for CO₂ reduction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Developing efficient catalysts is crucial for electrochemical carbon dioxide (CO2) reduction to support a carbon-neutral energy cycle.
• Earth-abundant, selective, and highly active catalysts are needed for technological advancements in CO2 electroreduction.

Purpose of the Study:

• To adapt an optical high-throughput screening method for studying multi-metallic catalysts in CO2 electroreduction.
• To identify highly active multi-metallic compositions for CO2 reduction using the developed screening method.
• To gain structural insights into the most active catalysts using X-ray scattering analysis.

Main Methods:

• Optical high-throughput screening of multi-metallic catalysts.
• Electrochemical testing for CO2 reduction and hydrogen evolution.
• X-ray scattering analysis, specifically the atomic pair distribution function (PDF) method, for structural characterization.

Main Results:

• Catalytic activity maps were constructed for various alloyed elements.
• Au6Ag2Cu2 and Au4Zn3Cu3 were identified as the most active ternary catalysts among Au, Ag, Cu, and Zn combinations.
• A five-fold increase in current density was observed for the best ternary catalysts compared to pure gold.
• Ternary catalysts exhibited higher selectivity for CO2 reduction to CO, with lower activity for hydrogen evolution compared to pure gold.

Conclusions:

• The developed high-throughput screening method is effective for identifying advanced multi-metallic catalysts for CO2 electroreduction.
• Ternary catalysts based on Au, Ag, Cu, and Zn show superior performance for CO2 reduction compared to binary combinations and pure gold.
• The identified catalysts demonstrate high selectivity towards CO production, contributing to efficient carbon capture and utilization strategies.