Grafting Nanolayers of Ni and Co Catalysts Around the Edges of Hierarchical Zeolite 13X by Leveraging the Crystal's Defects for CO ₂ Methanation

ABSTRACT Catalytic CO ₂ methanation offers a sustainable approach to convert waste CO ₂ into high‐value methane (CH ₄ ). However, designing highly efficient and stable catalysts that operate under harsh conditions remains a significant challenge. The interaction between the active metal and the support material (MSI) plays a critical role in determining the activity and stability of the catalyst. Here, we report the tailoring of MSI by regioselective anchoring of Ni and Co around the edges of hierarchical porous zeolite 13X (h13X), leveraging crystal defects modulated by amine and silanol groups. Scanning transmission electron microscopy and electron energy loss spectroscopy analysis confirmed the growth of approximately 3‐nm thick nanolayers of Ni and Co around the edges of h13X crystals. The XPS and H ₂ ‐TPR analysis of the catalysts revealed shifts in binding energies and reduced H ₂ consumption, corroborating stronger MSI and electronic interaction between Ni and Co. The optimized catalyst (AF‐7.5NiCo/h13X) exhibited a maximum CO ₂ conversion of 74.4% with a CH ₄ selectivity of 98% at 20 bar and 400°C under a GHSV of 60,000 mL g _cat ⁻¹ h⁻¹ and an activation energy of 55 kJ mol⁻¹. More importantly, the catalyst demonstrated stability, with consistent CO ₂ conversion performance over a month, showing no discernible decrease. The enhanced and stable performance of the catalyst is attributed to the stronger MSI and the sub‐5‐nm thin layers of Ni and Co over h13X.