Preferential Methanation of CO using Halogen‐Doped (F, Cl, Br) Ceria‐Supported Nickel Catalysts

Halogen‐doped Ni(F)/CeO2, Ni(Cl)/CeO2, and Ni(Br)/CeO2 catalysts were prepared by treating halogen‐free Ni/CeO2 with aqueous solutions of NH4F, NH4Cl, and NH4Br, respectively. It was demonstrated that the halogen dopants had distinct effects on the catalyst properties for the CO preferential methanation using realistic reformate gas: fluorine did not change catalytic activity, chlorine inhibited CO2 methanation activity and provided high selectivity towards CO methanation, and bromine completely inhibited both the CO and CO2 methanation activity. Selectivity tuning: Halogen doping strongly influenced the Ni/CeO2 catalyst properties in the preferential methanation of CO (CO‐SMET): fluorine did not change catalytic activity, chlorine inhibited CO2 methanation activity providing high selectivity towards CO methanation, and bromine totally inhibited both CO and CO2 methanation activity. Thus, controllable poisoning with chlorine provides a unique opportunity to improve the CO‐SMET performance of Ni/CeO2 catalysts