| In this paper, the perovskite-type nano-particles LaMnO3 is prepared by the sol-gel method, and we closed two doping systems for our research, these are Sr substituted A-site and Cu doped B-site, La1-xSrxMnO3 and LaCuxMn1-xO3(x=0.1, 0.2, 0.3,0.4, 0.5),the main contents and results are as following:The effects of conditions of the preparation on particles are studied by X-ray diffraction spectrum analysis(XRD)and scanning electron microscopy (SEM).Then the optimum conditions of the preparation of LaMnO3 nano-particles were ascertained that is: water bath temperature 70℃, PH=7, the citric acid dosage to total metal ions is 1, and the amount of substance ratio of EDTA to total metal ions is 1, after freeze drying then calcining under 750℃for 2h.The LaMnO3 nano-particles after A or B site doping nano-particles are prepared which referred to the optimum process. The structure and surface shape of La1-xSrxMnO3 and LaCuxMn1-xO3 is also studied. The results indicate that the crystal structure and phase composition has been great effected with the different doped amount. These are a perovskite structure with x=0.2 after A or B site doping, and display small size, uniform and dispersive.Catalytic performance of the obtained catalyst is tested by the wet air oxidation experiments. Tests results show that nano-particles has excellent catalytic oxidation performance, and with the increase of doping amount, the catalytic activity of the particle increase first and decrease afterwards with the increase of A or B site doping amount, the best performance presents at X=0.2 of A or B doping concentration. The difference between Sr -and Cu-doped lanthanum manganate was investigated. Both catalytic performance change have a the same change with the increase of doping amount. Under the same doping amounts, the catalytic performance of B-site doped is better than A-site. B ion directly involved in catalytic reaction, A ion does not participate in catalytic reaction, so B-site doped catalytic is better. |
PDF Full Text Request