The Effect of CeO2 Preparation Method on the Carbon Pathways in the Dry Reforming of Methane on Ni/CeO2 Studied by Transient Techniques

The present work discusses the effect of CeO2 synthesis method (thermal decomposition (TD), precipitation (PT), hydrothermal (HT), and sol-gel (SG)) on the carbon pathways of dry reforming of methane with carbon dioxide (DRM) applied at 750 degrees C over 5 wt% Ni/CeO2. In particular, specific transient and isotopic experiments (use of (CO)-C-13, (CO2)-C-13, and O-18(2)) were designed and conducted in an attempt at providing insights about the effect of support's preparation method on the concentration (mg g(cat)(-1)), reactivity towards oxygen, and transient evolution rates (mu mol g(cat)(-1) s(-1)) of the inactive carbon formed under (i) CH4/He (methane decomposition), (ii) CO/He (reverse Boudouard reaction), and (iii) the copresence of the two (CH4/CO/He, use of (CO)-C-13). Moreover, important information regarding the relative contribution of CH4 and CO2 activation routes towards carbon formation under DRM reaction conditions was derived by using isotopically labelled (CO2)-C-13 in the feed gas stream. Of interest was also the amount, and the transient rate, of carbon removal via the participation of support's labile active oxygen species.