Interfacial synergistic catalysis over Ni nanoparticles encapsulated in mesoporous ceria for CO2 methanation

An ordered mesoporous ceria, mpCeO(2), was synthesized using nanocasting, followed by strong electrostatic adsorption to prepare Ni nanoparticles encapsulated in mpCeO(2) for CO2 methanation. At 225 degrees C, TOF of Ni/mpCeO(2) catalyst (0.183 s(-1)) is 3 times higher than that of Ni catalyst supported on conventional CeO2 prepared by the same method (0.057 s(-1)). Characterization results indicate that encapsulated structure provides rich NiCeO2 interface with more oxygen vacancies, playing a key role in CO2 activation. As evidenced by in-situ DRIFTS experiments, CO2 activation over Ni/mpCeO(2) catalyst occurs through combined associative and dissociative mechanisms. Moreover, small and highly dispersed Ni nanoparticles in channels of mpCeO(2) facilitate H-2 dissociation, supplying sufficient *H for CO hydrogenation with *HCO intermediate species and leading to high CH4 selectivity. In addition to enhanced low-temperature activity and selectivity, Ni/mpCeO(2) catalyst is very stable throughout 70 h since metal sintering can be inhibited by confinement effect of mesoporous structure.

Automated summary

An ordered mesoporous ceria, mpCeO(2), was synthesized using nanocasting, followed by strong electrostatic adsorption to prepare Ni nanoparticles encapsulated in mpCeO(2) for CO2 methanation. The Ni/mpCeO(2) catalyst showed significantly improved activity and selectivity compared to conventional CeO2-supported Ni catalyst, with the encapsulated structure and highly dispersed Ni nanoparticles playing key roles. Additionally, the mesoporous structure inhibited metal sintering, leading to excellent stability of the catalyst.