Effect of preparation method on MnO_x-CeO₂ catalysts for NO oxidation

【摘要】 The NO oxidation reaction was studied over MnOx-CeO2 catalysts prepared by co-precipitation,impregnation and mechanical mixing method,respectively.It was found that the co-precipitation was the most active and a 60% NO conversion was achieved at 250 ℃.X-ray diffraction (XRD),Brumauer-Emmett (BET),H2-temperature programmed reduction (H2-TPR) and oxygen storage capacity (OSC) techniques were employed to characterize the physical and chemical properties of the catalysts.XRD results showed that amorphous MnOx or Mn-O-Ce solid solution existed in co-precipitation and impregnation prepared sample,while crystalline MnOx was found in mechanical mixing catalyst.A larger surface area was observed on co-precipitation prepared catalyst compared to those prepared by impregnation and mechanical mixing.The strong interaction between MnOx and CeO2 enhanced the reducibility of the oxides and increased the amount of Mn4+ and activated oxygen,which are favorable for NO oxidation to NO2.更多还原

【Abstract】 The NO oxidation reaction was studied over MnOx-CeO2 catalysts prepared by co-precipitation,impregnation and mechanical mixing method,respectively.It was found that the co-precipitation was the most active and a 60% NO conversion was achieved at 250 ℃.X-ray diffraction (XRD),Brumauer-Emmett (BET),H2-temperature programmed reduction (H2-TPR) and oxygen storage capacity (OSC) techniques were employed to characterize the physical and chemical properties of the catalysts.XRD results showed that amorphous MnOx or Mn-O-Ce solid solution existed in co-precipitation and impregnation prepared sample,while crystalline MnOx was found in mechanical mixing catalyst.A larger surface area was observed on co-precipitation prepared catalyst compared to those prepared by impregnation and mechanical mixing.The strong interaction between MnOx and CeO2 enhanced the reducibility of the oxides and increased the amount of Mn4+ and activated oxygen,which are favorable for NO oxidation to NO2.更多还原