Silver Catalyst: A Game-Changer in the Fight Against Carbon Emissions Through Efficient CO₂ Conversion

This diagram represents the silica-hydroxide cycle occurring during the electrochemical CO₂ reduction reaction using a silver-silica reduction electrode. The silica undergoes a weathering effect due to the hydroxide ions generated during the CO₂ reduction reaction, dissolving into a liquid state and then precipitating back near the anion exchange membrane, transforming back into silica on the reduction electrode, enabling a reversible process. This process prevents the hindered transfer of CO₂, allowing high-performance CO₂ electrolysis. Credit: Korea Institute of Science and Technology

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Researchers at the Korea Institute of Science and Technology (KIST) have developed a silver-silica composite catalyst inspired by Earth's natural geochemical cycles.

This catalyst demonstrates reversible local pH control through a silica-hydroxide cycle, addressing performance issues in CO₂ conversion at high current densities.

The silver-silica composite catalyst showed nearly 100% selectivity even at a higher current density of 1 A cm⁻², compared to commercial silver catalysts that drop to about 60% selectivity at 800 mA cm⁻²

.Additionally, the catalyst boosted CO₂ conversion to CO by around 47%, achieving high efficiency even at elevated current densities.

This development is significant because:

1. It maintains catalyst performance without altering its physical structure, relying solely on a chemical approach.

2. It enhances CO₂ reduction performance and durability at high current densities.

3. It improves the commercial potential of Carbon Capture and Utilization (CCU) technology for electrochemical CO₂ conversion.

The research team plans to optimize production processes for high-efficiency catalysts and conduct long-term durability testing for potential application in industrial facilities, such as power plants and petrochemical factories.

This advancement in silver-based catalysts for CO₂ conversion aligns with global efforts to mitigate carbon emissions and develop sustainable energy solutions. It represents a promising step towards more efficient and commercially viable CO₂ reduction technologies.

The upper figure depicts the CO₂ reduction reaction at an appropriate current density, while the lower figure illustrates the CO₂ reduction reaction at a high current density in a diagrammatic form. In the CO₂ reduction reaction, hydroxide ions (OH⁻) are generated more abundantly at high current densities, combining with CO₂ and preventing its transfer to the catalyst surface, which reduces performance. Credit: Korea Institute of Science and Technology