• • Alkali modification with 10% NaOH for 2 h increased the specific surface area and alkaline site density of 15%Ni/Al2O3 monolithic catalysts, leading to enhanced catalytic activity and CH4 selectivity.
• • Under H2/CO = 3:1, space velocity 10000 mL/(g·h), and 400 °C, the 15%Ni/Al2O3-2h catalyst achieved 97% CO conversion and 100% CH4 selectivity, outperforming unmodified catalysts.
• • Stability tests over 2 h showed that the 15%Ni/Al2O3-2h catalyst maintained a CO conversion of approximately 98%, demonstrating excellent long-term stability for industrial methanation processes.
• • The use of cordierite as a monolithic support provides a structured catalyst with improved heat and mass transfer, addressing a key bottleneck in conventional packed-bed reactors for exothermic methanation reactions.