Sustainable Dual-Template Fabrication of Hierarchical Pore Structure for Enhanced and Stable CO₂ Capture

Micropores significantly impact the adsorption properties of porous materials, but their effective utilization often encounters diffusion limitations. Introducing hierarchical pore structures offers a promising solution. However, the sustainable fabrication of hierarchical structures remains challenging. Additionally, previous fabrication methods typically involve the use of nitrogen-containing compounds, complicating the exploration of the relationship between pore structure and CO₂ capture properties due to CO₂’s strong affinity for N-containing groups. Here, we report a dual-template approach to sustainably fabricate hierarchically porous carbon (HPC) and systematically investigate the effect of pore hierarchy on CO₂ capture. The resulting interconnected multiscale porous adsorbent exhibits superior CO₂ capture properties than that of other nitrogen-free porous adsorbents. The pore structure with high hierarchy, encompassing extra-large, macro-, meso-, and microscale features, shows a 27% enhancement in CO₂ capture capacity compared to that without extra-large and mesopores. Moreover, this HPC retains its uptake capacity and kinetics after 20 adsorption–desorption cycles, showcasing robust stability. This study provides a sustainable strategy for optimizing micropore sites, offering valuable insights for the design of advanced porous materials tailored for adsorption-related applications.