Preparation Of Cu-Mn Composite Catalyst And Study On CO Catalytic Performance

Copper-manganese composite oxides have good performance in catalytic oxidation of CO.Concentrated sulfuric acid is often used in industrial production for redox reactions,which is not conducive to environmental protection and safety issues.Finding a green and environmentally friendly synthetic process route is the current research hotspot.In this paper,copper-manganese composite oxide catalysts were modified and synthesized by hydrothermal method,organic acid-assisted,microwave-assisted,and organic reducing agent-assisted methods,and the effects of various reaction conditions on the materials were investigated on this basis.During the experiment,the prepared materials were characterized and analyzed by XRD,SEM,BET,FT-IR,AAS and so on,and the materials were tested for catalytic oxidation by a CO catalytic activity evaluation device.The main experimental content is as follows:(1)A copper-manganese composite oxide catalyst is prepared by a hydrothermal method.By controlling the reaction temperature,its microstructure formed a nanowire structure with a diameter between 20 nm and 50 nm.The experimental results revealed that the prepared material showed a certain catalytic activity when the hydrothermal reaction temperature was 120?,the reaction time was 10 h,the calcination temperature was 300?,the calcination time was 3 h,and the ratio of Cu/Mn was 1:2.At low temperature(30?),the CO conversion efficiency was basically maintained at 25%within 1 h.(2)Copper-manganese composite oxide catalysts were prepared by assisted reactions of organic acids(acetic acid,oxalic acid,and citric acid).Among them,citric acid-assisted synthesis had the highest catalytic efficiency.The amorphous CuMnO_x composite catalyst had good catalytic activity for CO at room temperature.When the amount of citric acid was 0.5 g,calcination temperature was 300?for 3 h,the most active catalyst was obtained.The catalytic efficiency of this material for CO at room temperature was more than 50%within 1 h.(3)Copper-manganese composite oxide catalysts were prepared by microwave-assisted reaction.By controlling the reaction conditions,the effects of changing microwave reaction power and reaction time on the catalyst were studied.The material's micromorphology changed from nanoparticles to nanowires and network structures.The experimental results revealed that when the microwave-assisted reaction power was 50 w,the reaction time was 20 min,the calcination temperature was 300?,the calcination time was 3 h,and the ratio of Cu/Mn was 1:2,the prepared catalyst had the best catalytic activity.At low temperature(30?),the CO conversion rate was basically maintained above 85%.(4)Copper-manganese composite oxide catalysts were prepared by an organic reducing agent.By controlling the single variables such as the concentration of the reactants,the ratio of the organic reducing agent,the calcination temperature and the calcination time,a material with better catalytic activity was obtained.The experimental results showed that when the concentration of the reactant was lower,the ratio of ethanol to water was 75:800(ml/ml),the obtained material had a higher catalytic activity after calcination at 300°C for 6 h.At low temperature(30?),the catalytic efficiency of CO was maintained above 90%within 1 h.And under the catalytic condition of 40?,the high stability could be kept for 13 h.