Stability of bimetallic Ni/CeO2???SiO2 catalysts during fuel grade bioethanol reforming in a fluidized bed reactor

Oxidative steam reforming of bioethanol has been investigated in a fluidized bed reactor under atmospheric pressure at 500 degrees C over Pt-Ni/CeO2-SiO2 and Ru-Ni/CeO2-SiO2 catalysts, prepared with a noble metal content in the range 0-3 wt%. A preliminary investigation of the bimetallic catalysts performance was performed under a simulated bioethanol/oxygen stream (C2H5OH:H2O:O-2:Ar = 10:40:5:45) at 500 degrees C and WHSV = 61.7 h(-1). Poor stability was recorded over the low-loaded samples of both the series and the highest ethanol conversion as well as H-2 yield after 25 h of time-on-stream were recorded over the 2 Pt-10Ni/CeO2-SiO2 catalyst. In fact, a growth in the content of the noble metal assured an improvement in terms of resistance towards deactivation. However, a further increase up to 2 wt% was detrimental for both Pt and Rh-based catalysts. The most durable catalyst (2 Pt-10Ni) was additionally tested under a raw bioethanol stream (commercial fuel grade bioethanol) for 100 h at 4.1 h(-1): complete conversion and a stable H-2 yield above 50% was obtained; the characterization of the spent catalyst mainly revealed the formation of filamentous coke, which is expected to cause a low extent of deactivation. As a result, no apparent activity loss was observed and the bimetallic catalyst appeared a promising candidate for reforming of crude ethanol. (C) 2021 Elsevier Ltd. All rights reserved.