摘要
The hybrid nanostructures, Ni-only and Ni-CeO nanoparticles decorated on Al O nanoparticle clusters (Ni-Al O NPC and Ni-CeO -Al O NPC, respectively), were successfully synthesized as catalysts for steam reforming of methane (SRM). A substantial amount of metal-support interface was created in the hybrid nanostructure via aerosol-based evaporation-induced self-assembly, by which ultrafine Ni crystallites (≈6 nm) and tunable chemical composition achieved simultaneously. Addition of Al O NPC increased metal surface area and also suppressed Ni sintering in the hybrid nanostructure during catalysis. Hybridization with CeO nanoparticles significantly improved catalytic activity and stability of the Ni-based catalyst, especially in the absence of Al O NPC, and the amount of coke formation was shown to be effectively suppressed by >3×. A superior high catalytic performance of the hybrid nanostructures achieved: a low starting temperature (400 °C), remarkable activity at low temperature (turnover frequencies of methane conversion of 0.8 s at 500 °C), ideal H yield (≈3× of the converted methane), and high operation stability over 8 h reaction. The work demonstrates a prototype study of gas-phase synthesis of hybrid nanocatalysts using Al O NPC as the support matrix to achieve a very high activity at a low-temperature operation of SRM, which has shown promise for an advance of methane-based energy applications.