Mn-based Perovskites And Noble Metal-based Catalysts Catalyze The Combustion Of Methane

With the increasing depletion of oil energy.How to achieve efficient use of energy by the people more and more attention.Natural gas is a very promising clean energy.The most important component of natural gas is methane.Because of the most stable,easiest and most abundant hydrocarbons,people pay more attention on it.Methane requirements high temperature in a conventional manner combustion.There will be new contaminants,such as NOx and CO.Catalytic combustion is an effective way to solve these problems.Catalysts with high activity and high stability has become a relentless pursuit of catalytic workers.In recent years,Microwave heating caused in the field of synthesis catalyst researchers’attention.The reaction rate is fast,energy efficient,environmentally friendly and many other advantages.In this articles,we use microwave method added Sr to the La Mn O_3.15oxide.We synthesized La_1-xSr_xMn O_3.15 catalysts.Sr as the alkaline-earth metal can be used as the perovskite A-site ion.The valence of Sr was lower than La³⁺.Sr can improve the catalytic activity.We found that La_0.8Sr_0.2Mn O_3.15 have the best catalytic activity.Conversion of methane at a temperature of 550℃was 84%.We will make La_0.8Sr_0.2Mn O_3.15as a supporter,and load of precious metal Pd.Study the effects of different amounts of Pd loading on the catalytic.The catalysts were characterized by XRD method.I found all catalysts keep La Mn O_3.15structure.TEM results show that the Pd species is dispersed in supporter.H₂-TPR,O₂-TPD and XPS was used to study reduced ability;store oxygen capacity and surface species.The experimental results show that the microwave synthesis Pd/La_0.8Sr_0.2Mn O_3.15 catalyst has more oxygen vacancy,can be strong reducibility.The Pd species exists in the form of Pd O.6%Pd/La_0.8Sr_0.2Mn O_3.15catalyst have the best performance.At a temperature of 550℃,the methane conversion was100%.In addition,we synthesized 4%Pd-y%Co/CeO₂ catalysts by microwave method.The purpose for the research of Co doped of Pd/CeO₂ affect the performance of catalyst.And compare with x%Pd/CeO₂and y%Co₃O₄/CeO₂catalysts.Through the N₂ adsorption desorption,H₂-TPR and O₂-TPD found that x%Pd-y%Co/CeO₂have lower performance than Pd/CeO_2,the quantity of oxygen vacancy is small,these may be lead to 4%Pd-y%Co/CeO₂ catalyst activity decline reasons.