High SO2 tolerant and long term reliability of MnSO4-coated Ni-based catalysts for CO2 methanation in coal fired flue gas

• MnSO 4 -coated Ni-based catalysts with good sulfur resistance are developed. • 2Mn@MNA catalyst exhibits optimal catalytic performance in the presence of SO 2 . • Sulfur tolerant comes from the inhibition of SO 2 adsorption by coating layer. • Offers a simple and effective strategy for designing the sulfur-tolerant catalysts. Ni-based catalysts are widely used for carbon dioxide (CO 2 ) methanation but are susceptible to sulfur poisoning in industrial applications such as coal fired flue gas. Although doping with sacrificial elements can improve sulfur resistance, these catalysts still face the challenge of deactivation as the sacrificial elements are gradually consumed over time. To address this issue, a MnSO 4 -coated Ni-based catalyst was synthesized using a stepwise impregnation method and applied to CO 2 methanation under sulfur-containing conditions. Catalytic performance demonstrated that the 2Mn@MNA catalyst exhibited optimal MnSO 4 loading and maintained long-term activity over 50 h in the presence of SO 2 . Comprehensive characterization and DFT calculations provided insights into the sulfur-resistance mechanism. It was revealed that the MnSO 4 coating was shown to effectively suppress SO 2 adsorption, which significantly reduced sulfur accumulation on the catalyst surface, consequently enhancing the sulfur resistance of the Ni-based catalyst. This investigation presented a promising strategy for designing sulfur-tolerant catalysts by suppressing SO 2 adsorption via the protective coating layer, offering sustainable solutions for CO 2 utilization under industrial conditions.