Highly stable and coke-resistant Zn-modified Ni-Mg-Al hydrotalcite derived catalyst for dry reforming of methane: Synergistic effect of Ni and Zn

• Four HT-derived, Zn-modified Ni-Mg-Al mixed oxides tested for CO 2 reforming of CH 4 . • NiMgAl-3Zn exhibits highest and most stable activity for 100 h. • Zn enhances metal-support-interaction. • Zn aids in gasifying carbon deposits, improves coking tolerance. Considering Zinc’s basic nature and its propensity to alloy with transition metals, the improvement in the activity and carbon deposition-resistance of hydrotalcite-derived NiMgAl for the dry reforming of methane (DRM) is investigated with various Zn loadings. The prepared catalysts are characterized by various spectrometric, microscopic, and temperature-programmed techniques. Compared to the unmodified catalyst, the NiMgAl catalyst modified containing 3 wt% Zn exhibited excellent DRM activity and stability for 100 h on stream without any observable deactivation. Characterization results indicate that adding Zn to NiMgAl significantly increases the metal-support interaction, stabilizes smaller Ni particles, and minimizes carbon nanotube (CNT) growth. These advantages are a result of enhanced catalyst basicity and Ni-Zn alloy formation. Further analysis via temperature-programmed surface reaction with CH 4 indicates a decrease in CH 4 decomposition rate and relatively facile carbon gasification, thus increasing resistance to deactivation by coking.