Structural investigation of LaCoO3 and LaCoCuO3 perovskite-type oxides and the effect of Cu on coke deposition in the partial oxidation of methane

LaCoO3 and LaCo0.8Cu0.2O3 perovskite-type oxides prepared by the polymerizable complex route were obtained as single phase and investigated in the partial oxidation of methane through temperature-programmed surface reactions (TPSR). Characterizations were carried out before and after the reactions under different feed streams CH4/O2/He = 2/1/37 and 5/1/64, and revealed a dynamic structural transformation in which the perovskite is collapsed towards lanthanum-based matrix and metal cobalt and copper. The copper-substituted perovskite showed better performance in the partial oxidation of methane leading to higher CH4 conversion and higher syngas production than LaCoO3 during the transient reaction. Furthermore, copper had significant effect against carbon deposition on the catalyst and it is suggested to be a very important dopant for perovskites applied in reactions with hydrocarbons.

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► Preparation of perovskite-type LaCoO3 and LaCoCuO3 catalysts.
► Dynamic structural transformation of the perovskite.
► LaCoCuO3 perovskite showed better performance in the partial oxidation of methane.
► Copper had significant effect against carbon deposition on the catalyst.
► High activity to syngas for LaCoO3 catalyst with formation of carbon filaments.