Single- and double-stage catalytic preferential CO oxidation in H2-rich stream over an α-Fe2O3-promoted CuO–CeO2 catalyst

Single- and double-stage catalytic preferential CO oxidation (CO-PrOx) over-Fe2O3-promoted CuO–CeO2 in a H2-rich stream has been investigated in this work. The catalyst was prepared by the urea-nitrate combustion method and was characterized by X-ray diffractometer (XRD), X-ray fluorescence (XRF), Brunauer–Emmet–Teller (BET), transmission electron microscope (TEM), and scanning electron microscope (SEM). The catalytic activity tests were carried out in the temperature range of 50–225 °C under atmospheric pressure. The results of the single-stage reaction indicated that complete CO oxidation was obtained when operating at a O2/CO ratio of 1.5, W/F ratio of 0.36 g s/cm3, and at a reaction temperature of 175 °C. At these conditions, H2 consumption in the oxidation was estimated at 58.4%. Applying the same conditions to the double-stage reaction, complete CO oxidation was found and H2 consumption in the oxidation was reduced about 4.9%. When decreasing the double-stage reaction temperature to 150 °C, the results elucidated that CO could be converted to CO2 completely while H2 consumption in the oxidation was further reduced to 33.5%. A temperature blocking 22 factorial design has been used to describe the importance of the factors influencing the catalytic activity. The factorial design was according to the experimental results. When adding CO2 and H2O in feed, reduction of CO conversion for single- and double-stage reaction is obtained due to a blocking of CO2 and H2O at a catalytic active site. Comparing CO conversion obtained when operating with/without CO2 and H2O in feed for single- and double-stage reaction, less reduction is achieved when operating in double-stage reaction.