Double perovskite anti-supported rare earth oxide catalyst CeO_(2)/La_(2)CoFeO_(6)for efficient ventilation air methane combustion

Ventilation air methane is one of available resources with a massive reserve.However,most of ventilation air methane is discharged into the air and pollutes the environment.Catalysts with high temperature resistance(>800℃)for ventilation air methane are very essential for utilization of the ventilation air methane.We mainly prepared catalysts CeO_(2)/La_(2)CoFeO_(6)and La_(2)CoFeO_(6)/CeO_(2)and comparative samples CeO_(2)and La_(2)CoFeO_(6)by the simple sol-gel method and calcined them under 9000C,and tested the catalytic performance of ventilation air methane combustion under the condition of 5 vol%H_(2)O.The experimental results show that the light-off temperature(T_(1O))and complete combustion temperature(T_(90))of the ventilation air methane combustion reaction of CeO_(2)/La_(2)CoFeO_(6)catalyst are 417.4 and 587.7℃,respectively.T_(1O)and Tgo of La_(2)CoFeO_(6)/CeO_(2)only reach 425.5 and 615.8℃.The T_(10)and T_(9O)of CeO_(2)/La_(2)CoFeO_(6)are 417.4 and 587.7℃,which are lower than those of La_(2)CoFeO_(6)[T_(10)=452.4℃and T_(90)=673.0℃)and La_(2)CoFeO_(6)/CeO_(2)(T_(10)=425.5℃and T_(90)=615.8℃).Therefore,the catalytic performance of the anti-supported rare earth oxide catalyst CeO_(2)/La_(2)CoFeO_(6)is better than that of La_(2)CoFeO_(6)and supported catalyst La_(2)CoFeO_(6)/CeO_(2).

Facile Synthesis of Mesoporous Co3O4 Nanoflowers for Catalytic Combustion of Ventilation Air Methane

Flower-like Co3O4 hierarchical microspheres composed of self-assembled porous nanoplates were pre- pared by employing Pluronic F127 block-copolymer as template. The samples were characterized by powder X-ray diffraction（PXRD）, scanning/transmission electron microscopy（SEM/TEM）, and nitrogen adsorption-desorption at 77 K. The results show that the catalytic activity of Co3O4 nanoflowers for the combustion of ventilation air methane is higher than that of commercial Co3O4. The superior catalytic performance of this material can be related to its dominantly exposed {112} crystal planes and higher content of surface Co3＋.

LaMnO_(3)(La_(0.8)Sr_(0.2)MnO_(3))Perovskites for Lean Methane Combustion:Effect of Synthesis Method

The effect of the preparation method on the properties of LaMnO3 and La0.8Sr0.2MnO3 perovskite was studied. Materials were prepared by four methods: sol-gel, chemical combustion, solvothermal and spray pyrolysis and characterized. The effect of the synthesis method on the texture, acid-base character of the surface, reducibility with hydrogen, oxygen desorption, surface composition and catalytic activity for combustion of lean methane was studied. It was found that synthesis method affects physicochemical properties of obtained materials-solvothermally produced materials exhibit well-developed surface area, presence of reactive oxygen species on surface and high catalytic activity for CH4 combustion. Generally, LaMnO3 and La0.8Sr0.2MnO3 perovskites show catalytic activity for lean CH4 combustion comparable or higher than the activity of 0.5 wt.% Pt/Al2O3 but lower than 1 wt.% Pd/Al2O3.