Key Insight: A copper nanocluster engineered at the atomic level selectively converts CO₂ into methanol, suppressing the unwanted production of formate.
Copper Nanocluster Breakthrough
A collaborative team from Tohoku University and the Indian Institute of Technology Indore has engineered a copper nanocluster that selectively converts CO₂ into methanol under mild conditions. This atomic-level design marks a significant step toward sustainable fuel production.
The Catalyst & Its Mechanism
The nanocluster, designated [S@Cu₅₀S₁₂(StBu)₂₀(CF₃COO)₁₂], features a core-shell architecture with a sulfide-templated inner core. This precise structure enables controlled modulation of the Cu(I)/Cu(II) ratio, a key factor in steering the reaction pathway.
In electrochemical CO₂ reduction at −1.0 V versus RHE, the nanocluster produced methanol with a Faradaic efficiency of approximately 19%. Critically, it suppressed formate formation to below 11%. In stark contrast, a similar nanocluster without the central sulfide ion (Cu₅₀) predominantly produced formate (38% Faradaic efficiency) and no methanol at all.
Scientific Significance
"This study provides the first clear evidence that precise modulation of the copper valence state in Cu nanoclusters can directly influence the selectivity of CO₂ reduction pathways," stated Professor Negishi of Tohoku University.
The study, published in JACS Au on June 30, 2026, demonstrates that by redirecting the reaction pathway away from formate and toward methanol—a valuable fuel and chemical—researchers are opening new possibilities for using inexpensive, abundant copper-based catalysts in sustainable chemistry.