Inducing nucleation of MOF-74(Ni) with sepiolite for construction of hierarchically porous composites to synergistically enhance CO2 adsorption and desorption performance

The synchronous enhancement of CO 2 adsorption capacity and desorption efficiency while reducing material costs, remains a major challenge in CO 2 capture technology. Metal–organic frameworks (MOFs) are frequently hindered by high synthesis costs, structural instability, and poor regenerability. Herein, MOF-74(Ni)@sepiolite (MOF-74(Ni)@SEP) composites with hierarchical pore structures are prepared via an in-situ hydrothermal method. Naturally abundant SEP serves as a morphology modulator, reducing energy barriers and facilitating crystal growth, thereby lowering synthesis costs. Additionally, SEP acts as a structural scaffold, anchoring onto the surface of MOF-74(Ni) to enhance thermal stability and construct a hierarchical pore network. Compared to pure MOF-74(Ni), the composite exhibits faster CO 2 diffusion and improved mass transfer, as confirmed by zero-length column (ZLC) analysis. Benefiting from these structural advantages, 2-MOF-74(Ni)@SEP-(100 °C,16 h) demonstrates excellent cycling stability, maintaining over 98 % of its CO 2 adsorption capacity after 10 cycles. Even under simulated flue gas conditions (338 K, humid and oxygen-containing), the composite maintains high CO 2 uptake, confirming its superior thermal and moisture tolerance. Mechanistic analysis reveals preferential coordination of CO 2 with Ni 2+ Lewis acid sites, while the hierarchical pore structure facilitates CO 2 desorption performance. This work provides a cost-effective and scalable pathway toward CO 2 capture under realistic industrial conditions.