Thermally Stable, Coke-Resistant Ni Nanoparticle Catalysts Prepared By Atomic/Molecular Layer Deposition for Dry Reforming of Methane

Dry reforming of methane (DRM) represents a promising approach for carbon dioxide utilization and syngas generation, and the syngas could be used for Fischer-Tropsch synthesis. Ni catalysts are more commercially attractive for DMR than noble metal catalysts. However, the stability of Ni catalysts is poor caused by sintering of the Ni particles and coking. Ni catalysts can be prepared by traditional method such as incipient wetness method; however, the Ni particle size is pretty large and not controllable. Previous studies indicated that coking could be decreased by using smaller Ni particles. In this study, we prepared Ni catalysts using atomic layer deposition (ALD) in a fluidized bed reactor. The Ni particles size is pretty small (3-5 nm). To increase the thermal stability of the nanoparticles, an ultra-thin porous alumina shell is coated on Ni nanoparticle surface. The porous alumina film is obtained by oxidation of molecular layer deposited aluminum alkoxide films. The core-shell catalysts exhibit excellent catalytic performance toward dry reforming of methane with carbon dioxide at 850 ^°C.