Synergistic Role of ZrO2 Promoter and Ni–NiO–ZrO2 Networks in Improving Ni Catalysts for Dry Methane Reforming at Low Temperature

In this work, a rational catalyst design based on interfacial architecture engineering is proposed for low-temperature dry methane reforming (DMR) at 550 °C. Ni-based catalysts containing 10 wt% Ni were developed on a γ-Al2O3 support modified with 9 wt% MgO–1 wt% ZrO2. Zirconia promoters were introduced either by dry impregnation or via an ammonia vapor-assisted route to construct a Ni–NiO–ZrO2 interfacial network. The effects of ZrO2 content (0, 1, and 3 wt%) and synthesis route on metal–support interactions, oxygen mobility, and coke resistance were systematically investigated. ZrO2 promotion increased the fraction of reducible Ni species and preferentially enhanced CO2 activation, thereby promoting the reverse water–gas shift (RWGS) reaction and lowering the H2/CO ratio. In contrast, ammonia vapor-assisted preparation induced the formation of an LDH-derived Ni–NiO–ZrO2 surface network, which increased the concentration of surface-accessible Ni species, suppressed excessive zirconia coverage, and significantly improved apparent oxygen mobility. These synergistic structural features are consistent with enhanced oxygen-assisted carbon removal and improved coke management through regulation of the nature of carbon species, leading to more balanced activation of CH4 and CO2. Overall, this study provides insights into interfacial structure–performance relationships for designing efficient Ni-based catalysts for CO2 utilization.