The influence of Ce doping and the precipitation method on structural properties and the catalytic activity of copper manganese oxides for CO oxidation at ambient temperature have been investigated. The catalysts were...The influence of Ce doping and the precipitation method on structural properties and the catalytic activity of copper manganese oxides for CO oxidation at ambient temperature have been investigated. The catalysts were characterized by means of the powder X-ray diffraction and N2 adsorption-desorption, the inductively coupled plasma atomic emission spectrometry, the temperature programmed reduction, diffuse reflectance UV-Vis spectra, and the X-ray photoelectron spectroscopy. It was found that after doping little amount of Ce in copper manganese oxide, CeO2 phase was highly dispersed and could prevent sintering and aggregating of the catalyst, the size of the catalytic material was decreased, the reducibility was enhanced, the specific surface area was increased and the formation of the active sites for the oxidation of CO was improved significantly. Therefore, the activity of the rare earth promoted catalyst was enhanced remarkably.展开更多
A three-stage methane gas （CH4） reduction of manganese ore, dissolution, and precipitation from solution procedure was conducted to synthesize MnO2 nanorods. Methane gas reduction was carried out at 850, 875, 900, 9...A three-stage methane gas （CH4） reduction of manganese ore, dissolution, and precipitation from solution procedure was conducted to synthesize MnO2 nanorods. Methane gas reduction was carried out at 850, 875, 900, 925, and 950℃ for 120 min. Precipitation of the a-MnO2 nanorods was performed in the temperature range of 25-90℃with a constant reaction time of 90 min. The morphology and particle size of the products were determined from scanning electron microscope （SEM） images and X-ray diffraction （XRD） patterns. The BET and BJH of the products were found out by the surface area analyzer. Reduction results indicated that MnO-rich phase is significantly formed at 950℃ as MnO2 phase disappears. Precipitation results also showed an average diameter size of - 50 nm for the embedding a-MnO2 nanorods with BET surface area of 174 m^2/g.展开更多
文摘The influence of Ce doping and the precipitation method on structural properties and the catalytic activity of copper manganese oxides for CO oxidation at ambient temperature have been investigated. The catalysts were characterized by means of the powder X-ray diffraction and N2 adsorption-desorption, the inductively coupled plasma atomic emission spectrometry, the temperature programmed reduction, diffuse reflectance UV-Vis spectra, and the X-ray photoelectron spectroscopy. It was found that after doping little amount of Ce in copper manganese oxide, CeO2 phase was highly dispersed and could prevent sintering and aggregating of the catalyst, the size of the catalytic material was decreased, the reducibility was enhanced, the specific surface area was increased and the formation of the active sites for the oxidation of CO was improved significantly. Therefore, the activity of the rare earth promoted catalyst was enhanced remarkably.
基金financial supports of the Islamic Azad University of Zanjan
文摘A three-stage methane gas （CH4） reduction of manganese ore, dissolution, and precipitation from solution procedure was conducted to synthesize MnO2 nanorods. Methane gas reduction was carried out at 850, 875, 900, 925, and 950℃ for 120 min. Precipitation of the a-MnO2 nanorods was performed in the temperature range of 25-90℃with a constant reaction time of 90 min. The morphology and particle size of the products were determined from scanning electron microscope （SEM） images and X-ray diffraction （XRD） patterns. The BET and BJH of the products were found out by the surface area analyzer. Reduction results indicated that MnO-rich phase is significantly formed at 950℃ as MnO2 phase disappears. Precipitation results also showed an average diameter size of - 50 nm for the embedding a-MnO2 nanorods with BET surface area of 174 m^2/g.
