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 methanation 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 N-2 physisorption, XRD, SEM, TEM, and TPR-H-2 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 degrees C and all CO was converted to CH4 after T > 225 degrees C. Moreover, 22.3% CH4 was formed and the CO level decreased below 100 ppm at 200 degrees C during the selective CO methanation activity test over this catalyst.