LOW TEMPERATURE STEAM REFORMING OF ETHANOL OVER PTNI/CEO2-NANOCUBE CATALYST

摘要

The steam reforming of ethanol at high temperatures (673 - 873 K) for hydrogen production has been extensively studied [1]. The major challenge of this process is catalyst deactivation mainly due to carbon formation [2]. One alternative is the low temperature steam reforming (LTSR) of ethanol (573 - 673 K). In this case, ethanol may undergo decomposition, yielding a mixture of H2, CH4 and carbon oxides. In addition, the WGS reaction is favored in that temperature range, contributing to the reduction of CO concentration. However, the development of suitable catalysts which are able to produce a H2 rich stream with very low CO concentration is still a challenge. The support plays a key role in the LTSR of ethanol. Partially reducible oxides such as ceria and ceria-containing mixed oxides are known to be highly active toward WGS. These supports may also contribute to enhancement of catalyst stability due to both high oxygen storage capacity (OSC) and oxygen mobility. CeO2 nanoparticles with different morphologies such as ceria nanorods (CeO2 - nr), nanocubes (CeO2 - nc), nanopolyhedra (CeO2 - np) may exhibit variable oxygen mobilities, due to the exposition of different lattice planes in ceria structure depending on the ceria shapes [3]. The aim of this work is to investigate the performance of Ni and PtNi supported on CeO2 with a nanocube morphology for LTSR of ethanol. A characterization study by several techniques (DRIFTS, TPSR of ethanol, XPS and in-situ XAFS was carried out. Catalyst promotion by Pt was found to significantly improve catalyst stability.