Preparation Catalysis Application Of Co-based And Fe-based Oxides Nanoparticles In N₂O Decomposition

Nitrous oxide?N₂O?,commonly known as a laughing gas,is a compound that is an important part of the global nitrogen cycle and acknowledged as the third biggest greenhouse gas after CO₂ and CH₄,which the global heating potential?GWP?is 310 times more powerful than carbon dioxide and 21 times of methane.N₂O has been recognized as a potential contributor to the destruction of the ozone in the stratosphere and people's physical health.It is imperative to reduce nitric oxide emissions.Direct catalytic decomposition of N₂O technology is that N₂O is decomposed into non-toxic N₂ and O₂ on the effect of catalyst content,which has the application prospect of N₂O emission reduction technology,and its core is to develop highly active N₂O decomposition catalysts directly.In this article,nanometer iron oxide and cobalt oxide catalysts were prepared by solvothermal method,hydrothermal methods and homogeneous precipitation methods,the effect of the method of preparation on catalytic properties was investigated.The preparation conditions of solvothermal method was focused on,which the influence of volume ratio of ethanol to water,reaction temperature,active metal source and its amount of substance were examined.The catalysts were characterized by XRD,SEM,XPS,H₂-TPR,BET,N₂O-TPD,O₂-TPD and so on.The catalytic performance for N₂O decomposition was evaluated.The results showed catalyst oxidation reducing,absorption-desorption ability of reactant,specific surface area and particle size of Iron oxide and cobalt oxide influence the catalytic performance for decomposition of N₂O.The preparation methods influence on the physicochemical properties of catalysts and catalytic activity,according to our studies we found that the catalytic activity of catalysts prepared by solvothermal method was the best.In this section,the iron oxide and cobalt oxide prepared by solvothermal method respectively were the?-Fe₂O₃ with perovskite structure and the Co₃O₄with spinel structure.The results showed that when iron oxide catalysts prepared by solvothermal method which volume ratio of ethanol to water is0.5:29.5 and the iron molar is 0.007 mol,had the better catalytic activity,T₁₀,T₅₀ and T₉₅,respectively,to 538 ^oC,586 ^oC and 628 ^oC;when cobalt oxide catalysts prepared by solvothermal method which volume ratio of ethanol to water is 1.5:28.5,the amount of cobalt is 0.005 mol and the reaction temperature is 160 ^oC,had the highest catalytic activity,T₁₀,T₅₀ and T₉₅,respectively,to 266 ^oC,325 ^oC and 410 ^oC;The results of a reaction preliminary mechanism for the nitrous oxide catalytic decomposition show that surface oxygen species of the cobalt spinel oxides catalyst were very important for decomposition of N₂O.