(751g) Influence of Ni-Zn Alloy Formation on Catalytic Activity and Coke-Resistance of Ni/Mg (Zn)(Al)O Catalyst for Dry Reforming of Methane

CO₂ (Dry) reforming of methane (DRM) has been considered as one of the most promising processes for the production of syngas (a mixture of H₂ and CO) from an industrial and economic point of view. This process not only to mitigate two major greenhouse gases (CH₄ and CO₂) but also yields an equimolar H₂ and CO. And which could be directly used via the Fischer-Tropsch synthesis process . However, one of the major drawbacks is rapid catalyst deactivation via coke deposition and active metal sintering, which hindering the large-scale applications. In this work, a series of Ni supported Mg (Zn)AlO catalysts with various Zn loading (1, 3, 5, and 10 wt%) have been prepared and examined for Dry reforming of methane at 650 °C. The as-synthesized catalyst XRD results reveal that Zn²⁺ successfully replaces Mg²⁺ ions, and it retains the hydrotalcite structure without any changes. After Ni impregnation on Mg-Zn-Al support, the hydrotalcite structure has reconstructed, which clearly shows support has a memory effect. H₂-TPR analysis indicates the metal-support interactions as well as Ni reducibility are increased with the addition of Zn. Moreover, TEM analysis shows Ni/Mg (Al)O has larger particles size (14.7nm) whereas Ni/Mg(3%Zn) AlO catalyst contain smaller particles size (9.3 nm), which firmly proves that Zn playing a vital role to gain high metal surface area and dispersion. The DRM activity results showed that Zn doped catalysts exhibited high activity, and stability compares to counterpart, among all the tested catalysts, 10wt% Ni/Mg(3wt%Zn) (Al)O catalyst showed, improved stability and activity. CH₄-TPSR/O₂-TPO indicates that alloying Ni with Zn controls CH₄ decomposition, consequently lowering coke deposition and enhancing catalytic stability. The obtained results envisioned that the addition of Zn was found significantly effective in keeping the Ni in its metallic state thereby enhancing its stability.