Selective CO methanation over NiO--Al$_{2}$O$_{3}$--ZrO$_{2}$ and Co$_{3}$O$_{4}$--Al$_{2}$O$_{3}$--ZrO$_{2}$ catalysts

NiO--Al_2O_3--ZrO_2 and Co_3O_4--Al_2O_3--ZrO_2 catalysts were prepared by three different co-precipitation methods, namely co-precipitation, surfactant-assisted co-precipitation, and surfactant-assisted co-precipitation with ultrasound mixing methods, and their activities were tested in selective CO methanation. Catalysts were characterized using N_2 physisorption, XRD, SEM, TEM, XPS, and TPR-H_2 techniques. CO methanation and selective CO methanation reactions were carried out. Catalysts prepared by surfactant assisted co-precipitation gave high surface area, uniform pore size distributions, and small pores. The NiO--Al_2O_3--ZrO_2 catalyst prepared by surfactant-assisted co-precipitation gave 50% CO conversion to CH_4 at 155 °C and all CO converted to CH_4 when T > 225 °C. For the selective CO methanation, the CO level decreased below 100 ppm at 200 °C over the NiO--Al_2O_3--ZrO_2 catalyst prepared by surfactant-assisted co-precipitation.