Developing efficient methods to reduce pollution and carbon emissions is a key scientific focus for achieving sustainable development. Natural photosynthesis decouples the light absorption and CO₂ reduction processes, offering new insights into utilizing intermittent solar energy. However, the low energy density and intermittent supply of solar energy pose challenges to controllable and efficient CO₂ conversion. To address this issue, integrating intermittent sunlight with residual heat has become a scientifically and practically significant approach.

The Air Purification New Technology team (AirPNT) from the Institute of Earth Environment of the Chinese Academy of Sciences, in collaboration with various domestic teams, has proposed an innovative approach to overcome the limitations of intermittent solar supply. This method collects hydrogen atoms and electrons via solar energy, enabling efficient CO₂ utilization.

Inspired by natural photosynthesis, this method stores electrons and hydrogen atoms in catalysts using sunlight and water (Fig. 1). These stored electrons and hydrogen atoms can be released under heating conditions, enabling CO₂ reduction at low temperatures. Proof-of-concept experiments employed Cu-loaded WO₃ catalysts (Cu/WO₃). Under illumination, photocatalytic water splitting generated hydrogen atoms and electrons, which were stored in Cu/WO₃, forming a metastable intermediate (Cu/HxWO₃). When heated at low temperatures (150–300°C), Cu/HxWO₃ released the stored electrons and hydrogen atoms, achieving effective CO₂ reduction. Additionally, the experiments confirmed the feasibility of using natural sunlight to drive the process (Fig. 2), offering a pathway to harness intermittent solar energy for efficient CO₂ utilization. 

This study builds on the team's recent research in developing reproducible and scalable technologies for pollution and carbon reduction. It represents a step forward in advancing green energy-driven CO₂ conversion technologies, with potential applications in sustainable energy production and industrial CO₂ management.  

The research, published in Nature Communications, was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences, the National Natural Science Foundation of China, and the Youth Cross-Team Scientific Research Project of the Chinese Academy of Sciences.

Fig. 1 Diagram illustrating the integration of intermittent sunlight and residual heat for on-demand CO₂ conversion with water. (Image by Shi, et al)

Fig. 2 Demonstration of utilizing natural light for on-demand CO₂ conversion. (Image by Shi, et al)