In Situ Studies of the Active Sites for the Water Gas Shift Reaction over Cu−CeO2 Catalysts: Complex Interaction between Metallic Copper and Oxygen Vacancies of Ceria
Citations Over TimeTop 10% of 2005 papers
Abstract
New information about the active sites for the water gas shift (WGS) reaction over Cu-CeO2 systems was obtained using in-situ, time-resolved X-ray diffraction (TR-XRD), X-ray absorption spectroscopy (TR-XAS, Cu K and Ce L3 edges), and infrared spectroscopy (DRIFTS). Cu-CeO2 nanoparticles prepared by a novel reversed microemulsion method (doped Ce1-xCuxO2 sample) and an impregnation method (impregnated CuOx/CeO2 sample) were studied. The results from all of the samples indicate that both metallic copper and oxygen vacancies in ceria were involved in the generation of active sites for the WGS reaction. Evidence was found for a synergistic Cu-Ovacancy interaction. This interaction enhances the chemical activity of Cu, and the presence of Cu facilitates the formation of O vacancies in ceria under reaction conditions. Water dissociation occurred on the Ovacancy sites or the Cu-Ovacancy interface. No significant amounts of formate were formed on the catalysts during the WGS reaction. The presence of strongly bound carbonates is an important factor for the deactivation of the catalysts at high temperatures. This work identifies for the first time the active sites for the WGS reaction on Cu-CeO2 catalysts and illustrates the importance of in situ structural studies for heterogeneous catalytic reactions.
Related Papers
- → The Water-Gas Shift Reaction(1980)1,005 cited
- → Mechanistic Studies of Water–Gas-Shift Reaction on Transition Metals(2011)131 cited
- → Reverse water-gas shift reaction: steady state isotope switching study of the reverse water-gas shift reaction using in situ DRIFTS and a Pt/ceria catalyst(2005)81 cited
- → In situ time-resolved characterization of novel Cu–MoO2 catalysts during the water–gas shift reaction(2007)31 cited
- → Cobalt/manganese oxide water gas shift catalysts(1988)37 cited