Enhanced catalytic activities and selectivities in preferential oxidation of CO over ceria-promoted Au/Al2O3 catalysts

The preferential oxidation of CO (CO-PROX) is a hot topic because of its importance in proton-exchange membrane fuel cells (PEMFCs). Au catalysts are highly active in CO oxidation. However, their activities still need to be improved at the PEMFC operating temperatures of 80-120 degrees C. In the present study, Au nanoparticles of average size 2.6 nm supported on ceria-modified Al2O3 were synthesized and characterized using powder X-ray diffraction, nitrogen physisorption, transmission electron and scanning transmission electron microscopies, temperature-programmed hydrogen reduction (H-2-TPR), Raman spectroscopy, and in situ diffuse-reflectance infrared Fourier-transform spectroscopy. Highly dispersed Au nanoparticles and strong structures formed by Au-support interactions were the main active species on the ceria surface. The Raman and Hz-TPR results show that the improved catalytic performance of the Au catalysts can be attributed to enhanced strong metal-support interactions and the reducibility caused by ceria doping. The formation of oxygen vacancies on the catalysts increased their activities in CO-PROX. The synthesized Au catalysts gave excellent catalytic performances with high CO conversions (> 97%) and CO2 selectivities (> 50%) in the temperature range 80-150 degrees C. (C) 2016, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.