Selective oxidation of carbon monoxide over CuO–CeO2 catalyst: Effect of hydrothermal treatment

Copper oxide–ceria (CuO–CeO2) catalyst for selective oxidation of carbon monoxide (CO) was prepared by co-precipitation and hydrothermal treatment methods and evaluated for catalytic activity in a reformate gas composition which simulated the produced gas from methanol steam reforming. By applying the condition of hydrothermal treatment, the catalytic activity of CuO–CeO2 catalyst was increased and the operating temperature window, in which the concentration of carbon monoxide was lower than 10 ppm, was widened. From the thermogravimetric (TG) results of hydrothermally treated catalyst precursor, CuO–CeO2 catalyst did not show any improvement in physical properties such as Brunauer Emmett Teller (BET) surface area, pore volume and average pore diameter, but the chemical stability might be enhanced by hydrothermal treatment. By hydrothermal treatment, cuprous ion in the CuO–CeO2 catalyst migrated to the surface of catalyst resulting in increased surface concentration of copper and formation of cupric oxide on the surface of catalyst during calcination. While increasing the calcination temperature (i.e. above 800 °C), the phase separation occurred with a part of copper and cupric oxide was formed on the surface of catalyst which was observed in X-ray diffraction (XRD) analysis.