Roles of highly ordered mesoporous structures of Fe–Ni bimetal oxides for an enhanced high-temperature water-gas shift reaction activity

Abstract

Highly ordered mesoporous Fe–Ni bimetal oxide (m-FeNi) catalysts synthesized using KIT-6 as a hard-template by a nanocasting method were investigated for an alternative high-temperature water-gas shift (HT-WGS) reaction. The as-synthesized m-FeNi at an optimal Ni/Fe ratio of 0.24 revealed significantly enhanced activity and stability with high CO₂ selectivity and small methanation activity, which were attributed to the well-dispersed Ni nanoparticles in Fe₂O₃–NiO frameworks caused by altering the reducibility of Fe nanoparticles. The contributions of Ni nanoparticles were found not only to enhance the reducibility of active FeOx species but also to increase the interaction of Fe₂O₃–NiO interfaces, and were responsible for the less aggregation of Fe nanoparticles and smaller coke depositions. The newly formed stronger interactions between the mesoporous Fe₂O₃ and highly dispersed NiO nanoparticles at their optimal amounts were responsible for the superior structural and catalytic stability of alternative m-FeNi metal oxides even under HT-WGS reaction conditions.