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.