Synergistic Effect of CeO2 in CH4/CO2 Dry Reforming Reaction over Stable xCeO2 yNi/MCM-22 Catalysts

Abstract

Ceria-supported Ni/MCM-22 catalysts with weight ratio of Ni:CeO2 (9:0, 9:4, 9:8, 9:12) were prepared by a sol–gel method. The effect of CeO2 on activity and stability of catalysts was evaluated at 700–750 °C with gas hour space velocity of 2.4× 104 mL g–1 h–1. The presence of CeO2 in Ni/MCM-22 suppressed effectively the accumulation of coke on active Ni0 sites via the oxygen storage capacity on the interface between elemental nickel and CeO-Si groups of MCM-22. H2 temperature-programmed reduction results illustrated that CeO2 reduced the interaction between Ni and MCM-22 and increased the high dispersion of Ni nanoparticles, which is easily reducible. The 8CeO2 9Ni/MCM-22 catalyst performed the best at 750 °C with the lowest carbon deposition during time on stream of 60 h, plausibly due to the presence CeO2, which promotes C–H activation. Moreover, the surface oxygen species on the catalyst can interact with the coke generated during reaction to suppress the formation of coke.