In Situ Immobilizing Ni Nanoparticles to FDU-12 via Trehalose with Fine Size and Location Control for CO2 Methanation

Encapsulating Ni nanoparticles inside the channels of ordered mesoporous materials with high dispersion should be an efficient strategy to improve both catalytic activity and stability for a Ni-based catalyst. In this work, a series of Ni/FDU-12 catalysts with Ni particle size and location control were designed and synthesized using an impregnation method, in which an ethylene glycol solution of trehalose was used as the delivery conveyor and sacrificial carbon template. This was because the eight hydroxyl groups of trehalose could be linked to Ni2+ ions to form a coordination complex of trehalose-Ni2+ due to the bridging character; meanwhile, trehalose promoted the wettability of the ethylene glycol solution of nickel nitrate with increasing its viscosity. The combined effects of complex and wettability result in narrow size distribution of NiO nanoparticles and a high dispersion of Ni species inside of the channels of the FDU-12 support. In addition, after calcination in inert flow, the carbonization of trehalose and residual ethylene glycol could provide carbon species inside the pores as the physical barrier to in situ immobilize Ni nanoparticles and hinder their migration during high-temperature reduction and catalytic performance tests. The designed Ni/FDU-12 catalysts exhibited high catalytic activity and stability for CO2 methanation due to the high Ni dispersion and special structure of immobilized Ni particles, and the addition of CeO2 could further improve their catalytic performance.