Gadolinium-Modified Nickel Catalysts for Enhanced CO ₂ Methanation

The influence of gadolinium (Gd) on nickel (Ni)-based catalysts for CO2 methanation was studied. By varying the Gd content at a fixed Ni loading, we observed an enhancement in the CO2 methanation TOF from 0.009 to 0.03 s–1 with increasing Gd content, attributed to improved CO2 adsorption and increased metal reducibility, while the site density remained largely unchanged. From in situ FTIR studies, a possible reaction mechanism for CO2 methanation on Gd-modified Ni catalysts was proposed. The monometallic nickel catalyst exhibited strong CO adsorption, leading to catalyst deactivation over time, while in the presence of Gd, a CO + formate pathway was observed. This change in the likely mechanism due to the presence of Gd suppressed strong CO adsorption and improved catalyst stability over time.