Human breath as a carbon dioxide source for organic synthesis

The capture and utilization of low-concentration CO₂ as a C1 feedstock for organic synthesis have emerged as important research areas. Although atmospheric CO₂ is an ideal carbon source for sustainable organic transformations, its extremely low concentration (0.04%) presents a significant challenge to the development of efficient CO₂ conversion processes. In this context, we turned our attention to human breath as an alternative CO₂ source, which contains approximately 4% CO₂. The capture and utilization of CO₂ from human breath is also expected to play an important role in sustaining life in space, where readily available carbon sources are scarce and exhaled CO₂ represents a valuable renewable carbon resource for life-support systems. Herein, we demonstrate that human breath can serve as a practical and readily available CO₂ source for the efficient synthesis of urea compounds. Furthermore, the prepared urea compounds proved to be effective co-catalysts for the CO₂ fixation with epoxides under pure CO₂.