Effect of Y-doping on the catalytic properties of CuO/CeO2 catalysts for water-gas shift reaction

CuO/ceria and CuO/Y-doped ceria catalysts were synthesized. The Y-modified supports (1.0, 2.5 and 5.0 wt% Y2O3) were prepared by coprecipitation. CuO (3 wt% Cu) was loaded by deposition-precipitation. Having in mind the known effect of Y3+ modification for the generation of oxygen vacancies in ceria, its positive role on the water-gas shift (WGS) performance was expected. However, the catalytic test showed a trend of decreased WGS activity by increasing the Y-dopant amount, nevertheless that the differences were not very substantial. On the basis of XRD, XPS, EPR, Raman spectroscopy and H-2-TPR results the explanation related to the key role of the oxygen mobility influenced by Y-doping could be proposed. The reason of the inferior WGS performance with increasing Y-content would be the higher amount of surface oxygen vacancies around Y3+ ions which disturbed the Cu-O-vac-Ce active sites for WGS reaction. Though, during the long run catalytic tests in WGS reaction a positive effect of Y-doping for improved stability of CuO/ceria catalysts was evidenced. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.