Researchers at National Taiwan University have made significant strides in understanding the unique ability of copper chalcogenides to convert carbon dioxide (CO2) into formate with remarkable selectivity. Their findings, published on December 3, 2025, in the journal Nature Communications, reveal a previously elusive charge-redistribution mechanism that helps explain this behavior, offering new insights into the dynamics of electrocatalysis.
For years, scientists have been intrigued by the effectiveness of copper chalcogenides in selectively converting CO2 into formate, a process typically associated with p-block metals like tin or bismuth. This behavior is particularly notable given that copper (Cu), a transition metal, generally exhibits limited product selectivity. Despite extensive research, the underlying reasons for this phenomenon remained unclear until now.
The research team employed advanced operando synchrotron-based X-ray spectroscopic techniques to capture direct spectroscopic evidence. Their experiments revealed that chalcogenide anions play a dual role in stabilizing the catalytic structure. They prevent the over-reduction of cuprous (Cu+) species into metallic copper (Cu0), which safeguards an electronic configuration conducive to forming mono-carbon intermediates such as carbon monoxide (CO) and formate. Furthermore, these anions induce a charge-redistribution process within the Cu+ sites, dynamically stabilizing O-bound formate intermediates. This process effectively directs the CO2 reduction pathway towards predominantly forming formate, suppressing competing pathways for CO and multi-carbon products.
The optimal catalyst, identified as CuS, demonstrated impressive performance, achieving a near-complete selectivity for formate with a remarkable 90% Faradaic efficiency at −0.6 V, while also exceeding an ampere-scale partial current. This efficiency indicates significant potential for scalability in industrial applications.
Hao Ming Chen, a distinguished professor of chemistry and co-corresponding author of the study, emphasized the importance 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. 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.”
The work not only advances the understanding of copper chalcogenides but also sets the stage for future research aimed at rational electronic modulation of electrocatalysts. It highlights how charge redistribution governs selective electrocatalysis, paving the way for more efficient carbon dioxide conversion technologies.
For more information, refer to Feng-Ze Tian et al.’s article titled “Charge Redistribution Dynamics in Chalcogenide-Stabilized Cuprous Electrocatalysts Unleash Ampere-Scale Partial Current Toward Formate Production,” published in Nature Communications (2025). DOI: 10.1038/s41467-025-64472-1.
