Influence of Pd and Rare Earth Metals Oxides (Ce, La) as Modifying Additives in the Co,Ni-Oxide Catalyst Compositions on the Process of Methane Oxidation

Abstract

NiO-Al₂O₃ and Co₃O₄ oxide catalysts modified with palladium and oxides of rare earth metals (Ce and La) and formed on structured cordierite supports have been studied in the process of methane oxidation at different O₂/CH₄ ratios. It is shown that methane oxidation proceeds without the formation of CO even at an O₂/CH₄ ratio of < 2 (in contrast to nickel-containing catalysts) in the presence of cobalt-containing catalysts modified with cerium and lanthanum oxides. The addition of CeO₂ promotes Co₃O₄ dispersion, increases the number of oxygen vacancies, and prevents agglomeration of the active phase of the catalyst at high temperatures. The modification of Co₃O₄-CeO₂/cordierite with palladium (0.1%) enhances its activity due to increased surface oxygen mobility as a result of the interphase interaction of palladium with cobalt oxides and ceria (according to the TPR-H₂ and XPS data).