Balancing performance and sustainability in integrated CO₂ capture and methanation via NiCeO₂-anionic clay hybrid materials

Résumé fourni par la source

Integrated CO₂ capture and methanation (ICCM) provides a direct route for converting captured CO₂ into synthetic methane, but its large-scale implementation is limited by material stability and sustainability. Here, we report NiCeO₂/ionic clay hybrid materials, where the ionic clay is a Mg Al carbonate layered double hydroxide (LDH) acting as an adsorbent matrix for NiCeO₂ catalytic nanoparticles. The hybrids exhibit enhanced CO₂ uptake, efficient low-temperature operation (300 °C) with 100% CH₄ selectivity, and excellent cyclic stability under ICCM conditions. Although the NiCeO₂/LDH hybrids show lower methane productivity per unit mass of total material than NiCeO₂ alone, they significantly improve catalyst utilization, producing up to four times more CH₄ per unit mass of NiCeO₂. Operando XANES reveals a reversible Ni 0 /Ni 2+ redox transition under alternating CO₂/H₂ atmospheres, demonstrating that the active Ni phase dynamically adjusts its oxidation state during CO₂ adsorption–hydrogenation cycles. Life cycle assessment demonstrates a markedly reduced environmental footprint for the hybrid materials compared with NiCeO₂ for the same methane output, highlighting NiCeO₂/LDH hybrids as sustainable and scalable platforms for integrated CO₂ capture and conversion.

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