Au/CuO-CeO₂ catalyst for preferential oxidation of CO in hydrogen-rich stream: Effect of CuO content

A series of Au/CuO-CeO₂ with various amounts of CuO was prepared. CuO-CeO₂ was prepared by co-precipitation and Au was loaded by deposition-precipitation. The aim of this study was to develop a catalyst which is highly active and selective in preferential oxidation of CO in hydrogen stream (PROX). These catalysts were characterized by N₂-sorption, XRD, TEM, HR-TEM, and XPS. The PROX reaction was carried out in a fixed bed continuous flow reactor with a feed of CO: O₂: H₂: He = 1.33: 1.33: 65.33: 32.01 in volume ratios. The incorporation of copper ion into ceria lattice increased the oxygen storage capacity of ceria and enhanced the activity of the catalyst. The excess CuO would present on the surface of CeO₂. Au particles were well dispersed well on the support and the particle size of gold was in the range of 2 and 4 nm. Au was the active species and CuO played the promoter role. Those CuO presented on the surface of CeO had negative effect for CO oxidation. The selectivity of oxygen reacting with CO increased with increasing CuO content. Adding suitable amount of CuO in Au/CeO₂ is beneficial for CO conversion and suppressing hydrogen oxidation in fuel cell operation condition.