Improved performance of Au/Fe2O3 catalysts promoted with ZrO2 and Nb2O5 in the WGS reaction under hydrogen-rich conditions

Effect of addition of the ZrO2 and Nb2O5 promoters on the activity and stability of the Au/Fe2O3 catalysts in the WGS reaction under hydrogen-rich conditions was studied. Results showed that this new catalyst possesses enhanced activity and stability under conditions common in fuel processors. Its CO conversion almost reached the maximum value 99% at 200 degrees C and maintained better stability compared with unmodified samples within 50 h on-stream. Detailed characterization including BET, XRD, HRTEM, XPS, XRF and H-2-TPR revealed that ZrO2 and Nb2O5 acted as structural promoters and a strong interaction between ZrO2 and Nb2O5 existed. The enrichment of Zr and Nb on the surface kept the gold and magnetite particles apart delaying sintering. More active gold sites, larger surface area and smaller magnetite particles were the main reasons for the enhanced performance.