Antisolvent Extraction Strategy for Fabricating Ceria-Doped Ni/MgAl2O4 Catalysts with Enhanced Sintering and Coking Resistance for Dry Reforming of Methane

Dry reforming of methane (DRM) converts CH₄ and CO₂ into syngas, contributing to both the reduction of greenhouse gas emissions and valorization of chemicals. In this work, an innovative antisolvent extraction approach was utilized to synthesize a Ce-modified Ni/MgAl₂O₄ DRM catalyst, which enables the uniform doping of catalysts under mild conditions and reduces energy consumption and environmental pollution during the preparation process. The results demonstrate that Ce incorporation facilitates both the dispersion and stabilization of active species, effectively mitigating the sintering tendency of metallic active sites. Additionally, it enhances CO₂ adsorption, increases the diversity of surface oxygen species, and reduces the surface acidity. These synergistic interactions effectively suppress excessive CH₄ decomposition, while mitigating carbon deposit accumulation. Among the synthesized catalysts, the 5Ni1Ce/MA catalyst (molar ratio: Ce/Ni = 1:5) demonstrated good stability under harsh conditions (800 °C, WHSV = 30,000 mL·g_cat^–1·h^–1). The conversion of CH₄ and CO₂ exhibited a minimal decline, decreasing from 93.1 to 92.4% and 93.5 to 93.1%, respectively. In contrast, the related value decreased from 91.8 to 85.7% and 92.3 to 82.7% for the blank catalyst without Ce modification, respectively. The thermogravimetric (TG) analysis showed that the carbon deposition on the catalysts significantly decreased from 30% (5Ni0Ce/MA) to 1.2% (5Ni1Ce/MA), further demonstrating the enhanced coking resistance by Ce addition. Furthermore, during 50 h stability test at 600 °C, the 5Ni1Ce/MA catalyst displayed no substantial decrease in conversion rates, indicating its excellent stability under prolonged operation at lower temperature.