Research at National Taiwan University has unveiled critical insights into the mechanism that allows copper chalcogenides to efficiently convert carbon dioxide (CO2) into formate. This breakthrough, published in Nature Communications on December 3, 2025, addresses a long-standing question in the field of catalysis, enhancing our understanding of selective CO2 reduction processes.
For years, scientists have been fascinated by the ability of copper chalcogenides to transform CO2 into formate with exceptional selectivity. This capacity is usually attributed to p-block metals such as tin or bismuth, rather than transition metals like copper (Cu), which typically show less product selectivity. Despite previous investigations, the underlying reasons for this unique behavior remained unclear.
The research team at National Taiwan University has now identified a charge-redistribution mechanism that clarifies this phenomenon. Utilizing advanced operando synchrotron-based X-ray spectroscopic techniques, they captured direct evidence explaining how these copper chalcogenides operate at a molecular level.
The findings indicate that chalcogenide anions play a dual role in the catalytic process. They stabilize the catalytic structure, preventing the over-reduction of cuprous (Cu+) species to metallic Cu0, which is crucial for maintaining an electronic configuration suitable for producing mono-carbon intermediates like carbon monoxide (CO) and formate. Additionally, these anions induce a charge-redistribution process within the Cu+ sites, dynamically stabilizing O-bound formate intermediates. This stabilization effectively guides the CO2 reduction pathway predominantly toward formate formation, allowing the catalysts to suppress competing CO and multi-carbon pathways.
The optimal catalyst identified in the study, CuS, exhibited an impressive 90% faradaic efficiency for formate at a voltage of −0.6 V and achieved a formate partial current exceeding an ampere-scale. Such performance demonstrates the potential for scalability in industrial applications, positioning these catalysts as promising candidates for CO2 reduction technologies.
Hao Ming Chen, a distinguished professor of chemistry and co-corresponding author of the study, emphasized the significance of these findings. “Copper chalcogenides have fascinated researchers for decades because of their enhanced formate selectivity, but the true origin of this behavior was never fully understood,” he stated. “Our study reveals that charge-redistribution dynamics redefine the fundamental principles governing CO2 reduction selectivity and offer a new design strategy for tuning catalyst electronic structure via chalcogen modification.”
This research marks a significant advancement in the field of electrocatalysis, providing a clearer understanding of how charge redistribution influences selectivity in CO2 reduction processes. The insights gained from this work could lead to the development of more efficient catalysts, contributing to efforts aimed at addressing climate change through carbon capture and conversion technologies.
For further details, refer to the study by Feng-Ze Tian et al, titled “Charge redistribution dynamics in chalcogenide-stabilized cuprous electrocatalysts unleash ampere-scale partial current toward formate production,” published in Nature Communications. The research is expected to pave the way for future innovations in the design of electrocatalysts.
