High-Performance Catalytic Four-Channel Hollow Fibers with Highly Dispersed Nickel Nanoparticles Prepared by Atomic Layer Deposition for Dry Reforming of Methane

Highly dispersed nickel (Ni) nanoparticles (NPs) with an average particle size of 4.3 nm were uniformly deposited on the outer surface, the inner channel surface, and inside the pores of 20 cm long four-channel α-Al₂O₃hollow fibers (HFs) by atomic layer deposition (ALD) for dry reforming of methane (DRM). Cerium oxide (CeO₂) was added to promote the catalytic performance of Ni/Al₂O₃-HF catalysts. Rationally designed filling methods, by tuning the reactor size and inert fillings, can reduce the catalyst bed voidage in a fixed bed reactor for better reactant gas distribution, effectively utilize the Ni reactive sites, and achieve excellent catalytic performance. It was found that the CeO₂-promoted Ni/Al₂O₃-HF catalyst was highly active and highly stable without deactivation during an overall 400-h DRM test at 850 °C. CeO₂with reversible valence states could participate in surface reactions; especially, the formation of CeAlO₃provided sufficient surface Ce³⁺for CO₂activation and enhanced the stability and reusability of the HF catalysts.