Three kinds of Pt/alumina catalysts were prepared by impregnation-hydrogen reduction, impregnation-hydrazine reduction and electroless plating methods. Their differences in the structures, specific areas and particle ...Three kinds of Pt/alumina catalysts were prepared by impregnation-hydrogen reduction, impregnation-hydrazine reduction and electroless plating methods. Their differences in the structures, specific areas and particle sizes were characterized by XRD, BET and TEM, respectively. Furthermore, their catalytic activities for the hydrogen iodide （HI） decomposition were evaluated in a fixed bed reactor. The results show that the catalyst 5%Pt/Al2O3 prepared by the electroless plating has the optimum catalytic properties for HI decomposition owing to the high dispersion of the platinum nano-particles （〈5 nm） on the alumina supports.展开更多
The monodispersed Co nanoparticles were successfully prepared by means of hydrogen plasma method in inert atmosphere. The particle size, specific surface area, crystal structure and morphology of the samples were char...The monodispersed Co nanoparticles were successfully prepared by means of hydrogen plasma method in inert atmosphere. The particle size, specific surface area, crystal structure and morphology of the samples were characterized by transmission electron microscopy （TEM）, BET equation, X-ray diffraction （XRD）, and the corresponding selected area electron diffraction （SAED）. The catalytic effect of Co nanoparticles on the decomposition of ammonium perchlorate （AP） was investigated by differential thermal analyzer （DTA）. Compared with the thermal decomposition of pure AP, the addition of Co nanoparticles （2%-10%, by mass） decreases the decomposition temperature of AP by 145.01-155.72℃. Compared with Co3O4 nano-particles and microsized Co particles, the catalytic effect of Co nanoparticles for AP is stronger. Such effect is attributed to the large specific surface area and its interaction of Co with decomposition intermediate gases. The present work provides useful information for the application of Co nanoparficles in the AP-based propellant.展开更多
Amorphous manganese oxides (MnO_(x)) were synthesized by facile hydrothermal reactions between potassium permanganate and manganese acetate.Synthesis parameters,including hydrothermal time and temperature and molar ra...Amorphous manganese oxides (MnO_(x)) were synthesized by facile hydrothermal reactions between potassium permanganate and manganese acetate.Synthesis parameters,including hydrothermal time and temperature and molar ratio of precursors,significantly affected the ozone removal performance and structure property of MnO_(x).Amorphous MnO_(x)-1.5,which was prepared at the Mn^(2+)/Mn^(7+)molar ratio of 1.5 under hydrothermal conditions of 120℃ and 2 hr,showed the highest ozone removal rate of 93% after 480 min at the room temperature,RH (relative humidity)=80%and WHSV (weight hourly space velocity)=600 L/(g·hr).The morphology,composition and structure of catalysts were investigated with X-ray diffractometer (XRD),Raman spectra,N_(2) physisorption,field emission scanning electron microscope (FESEM),X-ray photoelectron spectroscopy (XPS),H2temperature-programmed reduction (H_(2)-TPR),O_(2) temperature-programmed desorption (O_(2)-TPD) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS).It was confirmed that high catalytic activity of amorphous MnOxfor ozone removal was mainly ascribed to its abundant oxygen vacancies,high oxygen mobility and large specific surface area.展开更多
基金the Foundational Research Project of National Defence(No.A1420080145)for thefinancial support.
文摘Three kinds of Pt/alumina catalysts were prepared by impregnation-hydrogen reduction, impregnation-hydrazine reduction and electroless plating methods. Their differences in the structures, specific areas and particle sizes were characterized by XRD, BET and TEM, respectively. Furthermore, their catalytic activities for the hydrogen iodide （HI） decomposition were evaluated in a fixed bed reactor. The results show that the catalyst 5%Pt/Al2O3 prepared by the electroless plating has the optimum catalytic properties for HI decomposition owing to the high dispersion of the platinum nano-particles （〈5 nm） on the alumina supports.
基金Supported by the National Natural Science Foundation of China （50306008, 50602024）.
文摘The monodispersed Co nanoparticles were successfully prepared by means of hydrogen plasma method in inert atmosphere. The particle size, specific surface area, crystal structure and morphology of the samples were characterized by transmission electron microscopy （TEM）, BET equation, X-ray diffraction （XRD）, and the corresponding selected area electron diffraction （SAED）. The catalytic effect of Co nanoparticles on the decomposition of ammonium perchlorate （AP） was investigated by differential thermal analyzer （DTA）. Compared with the thermal decomposition of pure AP, the addition of Co nanoparticles （2%-10%, by mass） decreases the decomposition temperature of AP by 145.01-155.72℃. Compared with Co3O4 nano-particles and microsized Co particles, the catalytic effect of Co nanoparticles for AP is stronger. Such effect is attributed to the large specific surface area and its interaction of Co with decomposition intermediate gases. The present work provides useful information for the application of Co nanoparficles in the AP-based propellant.
基金supported by the National Natural Science Foundation of China (No. 42077198)the Liao Ning Revitalization Talents Program (No. XLYC1907185)the Fundamental Research Funds for the Central Universities (No. N2025011)。
文摘Amorphous manganese oxides (MnO_(x)) were synthesized by facile hydrothermal reactions between potassium permanganate and manganese acetate.Synthesis parameters,including hydrothermal time and temperature and molar ratio of precursors,significantly affected the ozone removal performance and structure property of MnO_(x).Amorphous MnO_(x)-1.5,which was prepared at the Mn^(2+)/Mn^(7+)molar ratio of 1.5 under hydrothermal conditions of 120℃ and 2 hr,showed the highest ozone removal rate of 93% after 480 min at the room temperature,RH (relative humidity)=80%and WHSV (weight hourly space velocity)=600 L/(g·hr).The morphology,composition and structure of catalysts were investigated with X-ray diffractometer (XRD),Raman spectra,N_(2) physisorption,field emission scanning electron microscope (FESEM),X-ray photoelectron spectroscopy (XPS),H2temperature-programmed reduction (H_(2)-TPR),O_(2) temperature-programmed desorption (O_(2)-TPD) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS).It was confirmed that high catalytic activity of amorphous MnOxfor ozone removal was mainly ascribed to its abundant oxygen vacancies,high oxygen mobility and large specific surface area.
