Selective CO methanation over CeO2 –ZrO2 -composed NiO and Co3O4 catalysts

CeO2–ZrO2 -composed NiO and Co3O4 catalysts were prepared by 3 different methods. Both CO methana- tion and selective CO methanation were carried out. All catalysts were prepared by (1) co-precipitation, (2) surfactant- assisted co-precipitation, and (3) surfactant-assisted co-precipitation with ultrasound mixing methods. Catalysts were characterized by using N2 physisorption, XRD, SEM, TEM, and TPR-H2 techniques. The highest surface area value, uniform pore size distribution, and pores having small diameters were observed for the catalysts prepared by using the surfactant and ultrasound. The NiO/CeO2 /ZrO2 prepared by the surfactant-assisted co-precipitation was the most active catalyst for CO methanation. It gave 50% CO conversion to CH4 at 150 °C and all CO was converted to CH4 after T 225 °C. Moreover, 22.3% CH4 was formed and the CO level decreased below 100 ppm at 200 °C during the selective CO methanation activity test over this catalyst.