Ni/CaO-ZrO2-Al2O3 Catalyst for CO2 Methanation: Enhanced Low-Temperature Activity and High-Temperature Sintering Resistance

• • At 250 °C and WHSV of 30000 mL/(g·h), the Ni/CaO-ZrO2-Al2O3 catalyst achieves 96% CO2 conversion and 100% CH4 selectivity, with a methane space-time yield of 257.5 mmol/(g·h), demonstrating superior low-temperature activity for power-to-gas applications. • • After 200 h aging at 600 °C, the dual-promoted catalyst shows minimal Ni particle growth and activity loss, whereas the Ca-only promoted catalyst suffers pronounced deactivation, highlighting the critical role of Zr in maintaining high-temperature sintering resistance. • • Ca and Zr promoters synergistically enhance Ni dispersion and surface basicity, which are key factors for the high low-temperature activity, as confirmed by physicochemical characterization. • • Zr addition stabilizes Ca species by forming Ca-Zr solid solutions, preventing the transformation of CaO to CaCO3 that would otherwise promote Ni sintering, thus ensuring long-term catalyst stability under industrial conditions.