Dual‐Functional NiMg2−xCaxAl‐Hydrotalcite for Integrated CO2 Capture and In Situ Methanation

Integrated carbon capture and conversion (ICCC) is a promising technology to achieve cost‐effective carbon capture, usage, and storage. The development of efficient dual‐functional materials (DFMs) is crucial for advancing ICCC in industrial applications. Herein, a series of NiMg 2− x Ca x Al‐hydrotalcite ( x = 0, 0.5, 1, 1.5, 2) DFMs are prepared and applied to integrated CO 2 capture and methanation. Characterization results illustrate that magnesium stabilizes the porous structure of hydrotalcite, and calcium significantly modulates surface basicity. Codoping of Mg and Ca yields merits of both functions and leads to increased methanation efficiency. By optimizing the catalyst and operating conditions, NiMg 0.5 Ca 1.5 Al‐hydrotalcite exhibits an excellent CO 2 adsorption capacity of 313 μmol g −1 DFM and methane yield of 225 μmol g −1 DFM with almost full selectivity toward methane at 320 °C. NiMg 0.5 Ca 1.5 Al‐hydrotalcite also exhibits good cyclability at 320 °C under ambient pressure. Overall, Mg and Ca codoped hydrotalcite offers a promising approach to construct bifunctional materials for efficient integrated CO 2 capture and in situ methanation.