Oxygen-enhanced WGS over ceria-supported Au–Co3O4 bimetallic catalysts

Abstract

Aiming at enhancing CO conversion in Water Gas Shift (WGS) for fuel cell application, a small amount of oxygen was added to reactor feed stream in Oxygen-enhanced WGS reaction (OWGS) over monometallic Co3O4 and bimetallic Au–Co3O4 catalysts, both supported on ceria and prepared by different methods. Both CO conversion and H2 yield were found to increase by the oxygen addition. Ceria-supported Co3O4 monometallic catalysts were prepared by incipient wetness impregnation and deposition precipitation methods (both with 10 wt.% of Co loading). Au incorporation was added by deposition precipitation method (1 wt.% of Au loading). The as prepared catalysts were characterized by a sort of different techniques in order to correlate their activity with the physicochemical properties. The accumulation of carbonates and H2O during reactions on the tested catalyst is revealed by O2-TPO. The results indicated a high dispersion of gold independent of the preparation method of Au–Co bimetallic catalysts. Gold incorporation at Co3O4/CeO2 catalysts was observed to increase the capacity to release lattice oxygen from the catalysts to oxidize CO at low temperatures than pure Co3O4/CeO2. OSC cycles demonstrated that gold-containing catalysts increase the CO2 formation at 120 and 250°C. Higher CO conversion is achieves in OWGS than in WGS, independent of the gold presence. Au–Co3O4/CeO2 show strong synergetic promoting effect in OWGS.