Porous CoCe composite catalyst prepared by hydrothermal assisted soft template method for CH4/CO2 dry reforming

Abstract

The CoCex composite catalysts prepared by hydrothermal assisted template agent CTAB, have superior catalytic performances for CH4/CO2 dry reforming (DRM). The physicochemical properties of the catalysts were investigated in depth with the help of XRD, H2-TPR, CO2-TPD, ICP, Quasi in-situ XPS and N2 adsorption–desorption measurements. The transition metal Co is the main active center in the DRM reaction, which can easily release the outer electrons in the reaction to activate the reactant molecules. The introduction of Ce species can promote the highly dispersed metal Co species and catalytic active centers to be formed, as well as the adsorption and activation of CO2 molecules by the catalyst. Ce species can produce strong electronic effects with Co species, which can promote the electron-deficient CeO2-δ and electron-rich Coδ- species to be formed. The formation of CeO2-δ species facilitates the adsorption and activation of CO2 molecules, and the active oxygen species on the CeO2-δ surface facilitates the oxidative activation for CH4 molecules. The CH4 and CO2 reactant molecules can be adsorbed and activated by the formed Coδ- species to form CH4-x (x = 0–4) and CO2δ- reactive species, which can promote the DRM reaction. The Co/Ce molar ratio has an important effect on the physicochemical properties and CO2 adsorption performance of CoCex catalysts. And the CoCe2 catalyst prepared at a 2.0 Co/Ce molar ratio exhibited superior catalytic performance and high stability for the DRM reaction. The CH4 and CO2 conversion of the CoCe2 catalyst reached 88.6%, and 52.1% at 700 °C, respectively. In addition, the CoCe2 catalyst can maintain high cycle stability for CH4/CO2 dry reforming.