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

In this study, 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 4-channel α-Al2O3 hollow 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-hr DRM test at 850 ºC. CeO2 with reversible valence states could participate in surface reactions; especially, the formation of CeAlO3 provided sufficient surface Ce3+ for CO2 activation and enhanced the stability and reusability of the HF catalysts.