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

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 CH4 indicates a decrease in CH4 decomposition rate and relatively facile carbon gasification, thus increasing resistance to deactivation by coking.