Abstract: CO₂ capture and in-situ conversion（iCCC） technology can play a crucial role in mitigating global climate change. When the iCCC technology is applied to the CO₂ capture from the high-temperature flue gas, its thermo-energy can be directly converted CO₂ into the syngas during CO₂ conversion at the same fixed bed. The rational design of efficient dual functional materials （DFMs） is key to achieve high-efficiency iCCC processes. Here, we synthesized a series of xNi-MgO/CaO DFMs with varying Ni/Mg ratios by a hard template method using NaOH-activated porous carbon spheres. The structure of the hollow microsphere not only reduces the diffusion resistance during CO₂ adsorption but also provides buffer space to accommodate the volume expansion of CaO/CaCO₃ during the iCCC process. In addition, the NiO-MgO solid solution formed within the confined space of the hollow microspheres acts as a physical barrier, isolating the catalytic Ni⁰ particles and effectively preventing the sintering of Ni nanoparticle at high temperatures. By optimizing the Ni/Mg ratio, reaction temperature, and H₂ concentration, the iCCC performance of the xNi-MgO/CaO DFMs were evaluated. Under the optimal reaction temperature of 650 ℃ and H₂ concentration of 10%, the 10Ni-MgO/CaO DFM exhibited a CO₂ adsorption capacity of 10 mmol/g, a CO₂ conversion efficiency above 94% with a 100% CO selectivity after 10 adsorption-conversion cycles. Kinetic studies further demonstrated that the confined space in the Ni-MgO/CaO DFM significantly enhances the reaction rates of iCCC to syngas.