Unique copper nanocluster design increases selectivity in CO₂ reduction

The humble copper (Cu) may not have the allure of gold or silver, but its incredible versatility makes it invaluable in cutting-edge research. A joint study by scientists from Tohoku University, Tokyo University of Science and the University of Adelaide has uncovered a way to increase the selectivity and sustainability of electrochemical CO2 reduction processes.

By manipulating the surface of Cu nanoclusters (NCs) at the atomic level, the team unlocked new possibilities for efficient and environmentally friendly carbon conversion technology. This landmark achievement not only demonstrates the transformative potential of copper in sustainable chemistry, but also highlights the important impact of global cooperation in addressing pressing challenges such as carbon emissions. .

The results were published in the academic journal Small on December 4, 2024.

Electrochemical CO2 reduction reactions (CO2RR) have attracted much attention in recent years due to their potential to convert excess CO2 in the atmosphere into valuable products. Among the various nanocatalysts studied, NCs have emerged as a standout due to their distinct advantages over larger nanoparticles.

Among this family, Cu NCs have shown great potential, offering diverse product formation, high catalytic activity, and sustainability. Despite these advantages, precisely controlling product selectivity on an industrial scale remains a challenge. As a result, current research focuses on improving these properties to maximize the potential of Cu NCs for sustainable CO2 conversion.

“To achieve this breakthrough, our team had to modify the NCs at the atomic scale,” said Professor Yuichi Negishi of Tohoku University. It was very difficult because we were so dependent on a lot of different parts.” It was like trying to move the pillars of a building. ”

They succeeded in synthesizing two Cu14 NCs with identical structural structures by changing the surface thiolate ligands (PET: 2-phenylethanethiolate, CHT: cyclohexanethiolate). Overcoming this limitation required the development of carefully controlled reduction strategies. This enabled the creation of two structurally identical NCs with different ligands, representing a major advance in NC design.

However, the research team observed variations in the stability of these NCs due to differences in interactions between the clusters. These differences play an important role in shaping the sustainability of these NCs in catalytic applications.

Although these NCs share nearly identical geometries derived from two different thiolate ligands, they exhibited markedly different product selectivities when tested for catalytic activity in CO2 reduction. These variations affect the overall efficiency and selectivity of CO2RR.

Negishi said, “These findings are critical to advancing the design of Cu NCs that combine stability and high selectivity, paving the way to more efficient and reliable electrochemical CO2 reduction technologies. It’s something that opens the door,” he concluded.