O-exchange evidenced in Ce-Ni-MFI catalysts during water gas shift reaction: Use of isotopic water (50% H218O - 50% H216O)

Abstract

This study provides a detailed O-exchange of Ce-MFI, Ni-MFI and Ce-Ni-MFI using isotopic water (50% H218O - 50% H216O) to better understand the reaction mechanism of the catalytic water gas shift reaction (WGSR) over different combinations of Ni and Ce incorporated in the MFI structure. The study showed high activity of incorporated Ce on water splitting, and explained how adding Ce to Ce-Ni-MFI as a catalyst in the WGSR increased its performance and selectivity. A detailed kinetic study was performed at low temperatures (503–533 K) on Ce-Ni-MFI (with 2 wt% Ni and 2 wt% Ce) using empirical, microkinetic and neural networks techniques. All these methods predicted the reaction rate very well. The suggested reaction mechanism from the microkinetic approach was consistent with the findings of the O-exchange study, and showed the cooperation of Ni and Ce to provide the required oxygen to oxidize CO on the Ni surface.