Charge-Buffered Lattice Enabled Redox-Stable Ni/Perovskite-CaO Dual-Functional Materials for Integrated CO ₂ Capture and Conversion

Integrated CO 2 Capture and Conversion with Dry Reforming of Methane (ICCC-DRM) offers a promising route for syngas production but is currently hampered by the rapid degradation of traditional Ni/CaO dual-function materials (DFMs) due to Ni sintering, coke deposition, and severe CaO volume expansion. Herein, we designed a redox-stable Ni/CaTi 0.95 Ce 0.05 O 3 /CaO composite DFM via a charge-buffering lattice strategy and unraveled the self-adaptive lattice breathing mechanism. Specifically, the Ce-induced lattice distortion activates lattice oxygen (O latt ) and lowers the migration energy barrier for Ni in the perovskite structure, thereby driving Ni self-regeneration at 650 °C. Crucially, the reversible Ce 3+ /Ce 4+ redox couple actively buffers the lattice stress induced by Ni self-regeneration via dynamic charge balancing. This mechanism maintains a stable oxygen vacancy ( V O ) concentration during cycling, thereby inhibiting structural deterioration. Furthermore, continuous CaO–CaTiO 3 phase boundaries facilitate intracrystalline CO 2 diffusion and act as mechanical buffers against volume stress. Consequently, the DFM exhibits high stability, retaining over 97% of the CO 2 capture capacity after 20 cycles and sustaining 75% of the CO 2 conversion with a near-unity H 2 /CO ratio over 60 long-term cycles. This robust cyclic stability demonstrates its strong potential for practical and long-term continuous CO 2 capture and conversion.