The preferential oxidation of CO in excess hydrogen: A study of the influence of KOH/K2CO3 on CuO–CeO2−x catalysts

The preferential oxidation of CO in rich hydrogen has been studied for CuO–CeO2−x catalysts. The catalysts were prepared by co-precipitation with K2CO3 + KOH as precipitators and characterized using N2 physisorption isotherms, high resolution transmission electron microscopy (TEM), and X-ray diffraction (XRD). The results indicate that nano-structured CuO–CeO2−x catalysts are obtained, and that the ratio of KOH/K2CO3 has a beneficial influence on the properties of CuO–CeO2−x catalysts, i.e., with the addition of KOH, the particle sizes grow smaller, CuO–CeO2−x catalysts have larger surface areas, CuO species in CuO–CeO2−x are more easily reduced and achieve higher catalytic performance in the preferential oxidation of CO in rich hydrogen. CO conversion higher than 99% with O2 selectivity of 100% is obtained for CuO–CeO2−x catalysts with KOH/K2CO3 equal to 4:0 at a temperature of 90–110 °C and a space velocity of 30,000–120,000 ml g−1 h−1.

Graphical abstractPrecipitators have a beneficial influence on the catalytic performance of nano-structured CuO–CeO2−x catalysts. The catalyst prepared with the KOH/K2CO3 ratio of 4:0 achieves the superior activity in the preferential oxidation of CO in rich hydrogen. CO conversion higher than 99% with O2 selectivity of 100% can be obtained over this CuO–CeO2−x catalyst at 90–110 °C and a space velocity of 30,000–120,000 ml g−1 h−1 in the absence of CO2 and H2O or at 150 °C and a space velocity of 120,000 ml g−1 h−1 in the presence of CO2 and H2O. Figure optionsDownload full-size imageDownload as PowerPoint slide