Effects of Ce/Zr ratio on the structure and performances of Co-Ce 1− xZr xO 2 catalysts for carbon dioxide reforming of methane

Abstract

The Co-incorporated Ce 1− x Zr x O 2 catalysts were prepared by co-precipitation for carbon dioxide reforming of methane. The ratio of Ce to Zr was varied to optimize the performances of co-precipitated Co-Ce-Zr-O x catalysts. The prepared catalysts were characterized by various physico-chemical characterization techniques including TPR, X-ray diffraction, N 2 adsorption at low temperature, XPS and CO 2-TPSR. The co-precipitated Co-Ce 0.8Zr 0.2O 2 sample containing 16% CoO exhibited a higher catalytic activity among the five catalysts, and the activity was maintained without significant loss during the reaction for 60 h. Under the conditions of 750 °C, 0.1 MPa, 36000 ml/(h·g cat), and CO 2/CH 4 molar ratio of 1 : 1, the CO 2 conversion over this catalyst was 75% while the CH 4 conversion was 67%. The cubic Ce 0.8Zr 0.2O 2 facilitated a higher dispersion and a higher reducibility of the cobalt component, and the apparent activation energy for Co-Ce 0.8Zr 0.2O 2 sample was 49.1 kJ/mol in the CO 2/CH 4 reforming reaction. As a result, the Co-Ce 0.8Zr 0.2O 2 sample exhibited a higher activity and stability for the reforming of CH 4 with CO 2.