Selective CO methanation over CeO_2--ZrO_2-composed NiO and Co_3O_4 catalysts


Abstract: CeO_2--ZrO_2-composed NiO and Co_3O_4 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/CeO_2/ZrO_2 prepared by the surfactant-assisted co-precipitation was the most active catalyst for CO methanation. It gave 50 % CO conversion to CH_4 at 150 ^°C and all CO was converted to CH_4 after T > 225 ^°C. Moreover, 22.3 % CH_4 was formed and the CO level decreased below 100 ppm at 200 ^°C during the selective CO methanation activity test over this catalyst.

Keywords: Surfactant, ultrasound, CeO_2--ZrO_2, methanation

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