Reaction-Induced Reversible Reconstruction Enhanced Ni-MgO/CaO Dual Functional Material for Stable CO₂ Capture and In...

Calcium looping dry reforming of methane (CaLDRM), which realizes CO₂ capture and in situ conversion to valuable syngas, presents a promising route for large-scale CO₂ fixation. However, its development is hindered by the scarcity of efficient and durable dual-functional materials (DFMs) that combine high capture capacity with stable catalytic activity. Herein, we construct a Ni-MgO/CaO DFM by engineering NiO-MgO solid solution (Mg_xNi_1-xO) on a hierarchically porous CaO support incorporating highly dispersed MgO. The modulated Mg_xNi_1-xO phase fosters a strong metal-support interaction to inhibit Ni agglomeration and carbon deposition, and simultaneously acts as a structural stabilizer to mitigate CaO sintering. The resultant material delivers a CO₂ uptake of 11.5 mmol g^-1, an in situ CO₂ conversion of 90 %, and a syngas yield of 55 mmol g^-1 at a relatively low temperature of 620°C, while exhibiting insignificant deactivation over 65 cycles, outperforming the previously developed CaO-Ni based DFMs. Mechanistic studies reveal that this material achieves a reaction-induced reversible reconstruction during the CaLDRM process, which not only sustains the Mg_xNi_1-xO-mediated structural stability enhancement but also ensures the high accessibility of catalytic sites, thereby decoupling the activity-stability trade-off. This work provides a practical material design strategy for efficient CO₂ capture and catalytic conversion processes.