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The methanation of CO and CO 2 present in coke oven gas was performed in a fixed-bed catalytic reactor at a reaction temperature between 200 and 400 °C. Different support materials, including SiO 2 , Al 2 O 3 , ZrO 2 , and CeO 2 , were doped with a different percentage of active metals using a standard impregnation and coprecipitation method. The catalysts were characterized using Brunauer−Emmett−Teller analysis, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and temperature-programmed desorption techniques. The activity of all samples was tested in terms of the percentage of CO and CO 2 conversion and CH 4 selectivity. The results were analyzed on the basis of the difference in the catalytic performance at different active metal loadings and support materials. The effect of the catalytic support on the reducibility, morphology, and active metal dispersion was investigated. The ZrO 2 −CeO 2 -supported catalyst prepared under coprecipitation can attain 100% CO conversion at around 300 °C and ≥95% CO 2 conversion at 400 °C and has a CH 4 selectivity of 99%.

A series of active oxygen material Ce x Zr 12x O 2 -supported NiACo bimetallic nanosized catalysts were prepared by coprecipitation method, which is simple and fit for industrial use with lower cost than other methods. The effect of CeO 2 / ZrO 2 mole ratio, Co metal addition, and PEG-6000 addition were investigated. The catalysts were characterized through X-ray diffraction, H 2 thermal-programmed reduction, N 2 adsorption, Raman spectroscopy, CO pulse chemisorption, X-ray photoelectron spectroscopy, oxygen storage capacity, and transmission electron microscopy-energy dispersive X-ray analysis. Modifications of the structural and redox properties of these materials were evaluated in relation to their catalytic performances. Particularly, the relationship between the active oxygen sites of the catalysts and their catalytic performances was investigated. The interaction between active metals (Ni and Co) and Ce x Zr 12x O 2 support was found to be very important for catalytic performance. The active oxygen site of Ce x Zr 12x O 2 can considerably improve catalytic performance. Appropriate Co metal addition also remarkably enhanced the catalytic stability and activity. Moreover, PEG-6000 addition can improve the Brunauer-Emmett-Teller surface area and active metal dispersion of catalysts to improve their performances. The nanosized catalyst 15 wt % Ni-5 wt % Co/Ce 0.25 Zr 0.75 O 2 prepared by adding 5 wt % PEG-6000 achieved almost 85% CO 2 conversion and 98% selectivity to methane at 280 C when the gas hourly space velocity was 10,000 h 21 .

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