Carbon dioxide reforming of methane over Ni incorporated into Ce–ZrO2 catalysts Original Research Article

A co-precipitation/digestion method was employed in a single step to prepare Ni–Ce–ZrO2 catalysts useful for carbon dioxide reforming of methane. The loading amount of Ni and the ratio of CeO2 to ZrO2 were systematically varied to optimize the co-precipitated Ni–Ce–ZrO2 catalysts. The prepared catalysts were characterized by various physico-chemical characterization techniques such as XRD, BET surface area, hydrogen chemisorption, SEM, TPR and XPS. It was found that 15% Ni (w/w) co-precipitated with Ce0.8Zr0.2O2 having cubic phase gave synthesis gas with CH4 conversion more than 97% at 800 °C and such activity was maintained without significant loss during the reaction for 100 h. On the contrary, Ni–Ce–ZrO2 having tetragonal phase (Ce0.2Zr0.8O2) or mixed phase (Ce0.5Zr0.5O2) deactivated during the reaction due to carbon formation. The enhanced catalytic activity and stability of the co-precipitated Ni–Ce0.8Zr0.2O2 catalyst is attributed to a combination of the nano-crystalline nature of cubic Ce0.8Zr0.2O2 support and the finely dispersed nano-sized NiOx crystallites, resulting in the intimate contact between Ni and Ce0.8Zr0.2O2 particles.