Hydrogen and ethylene production from partial oxidation of methane on CuCe, CuZr mixed oxides and ZrO2 catalysts Original Research Article

We prepared non-stoichiometric oxides based on CuO, CeO2 and ZrO2 and determined main structural properties that were tested in the partial oxidation of methane (POM). XRD results indicate that Cu is finely dispersed. It indicates the presence of a CuxCeyOz phase or a solid solution. In situ XRD of the CuCe sample at different temperatures and reduction conditions was obtained to verify the influence of pretreatment. For the CuCe and ZrO2 samples the conversion of methane increases with temperature, reaching maximum conversion at 850 °C, which are close to the equilibrium values, On the other hand, the conversion for the CuZr is much lower. The ethylene selectivity increases above 700 °C for CuCe and ZrO2 and reached 92% at 850 °C on the CuCe and 83% at 800 °C on the ZrO2 and on opposite, low ethylene selectivity for the CuZr catalyst. Both CuCe and ZrO2 are excellent catalysts for ethylene production but less important for H2 production in the partial oxidation of methane. Redox properties of CeO2 and the presence of Cu in the CuCe catalyst favor the formation of Ce ions that may be responsible for the oxygen migration to the molecular methane and formation of CH− radicals.