Charge-Buffered Lattice Enabled Redox-Stable Ni/Perovskite-CaO Dual-Functional Materials for Integrated CO2 Capture and Conversion

Integrated CO2 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/CaTi0.95Ce0.05O3/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 (Olatt) and lowers the migration energy barrier for Ni in the perovskite structure, thereby driving Ni self-regeneration at 650 °C. Crucially, the reversible Ce3+/Ce4+ redox couple actively buffers the lattice stress induced by Ni self-regeneration via dynamic charge balancing. This mechanism maintains a stable oxygen vacancy (VO) concentration during cycling, thereby inhibiting structural deterioration. Furthermore, continuous CaO–CaTiO3 phase boundaries facilitate intracrystalline CO2 diffusion and act as mechanical buffers against volume stress. Consequently, the DFM exhibits high stability, retaining over 97% of the CO2 capture capacity after 20 cycles and sustaining 75% of the CO2 conversion with a near-unity H2/CO ratio over 60 long-term cycles. This robust cyclic stability demonstrates its strong potential for practical and long-term continuous CO2 capture and conversion.