Effects of La_2O_3 contents on the Pd/Ce_（0.8）Zr_（0.2）O_2-La_2O_3 catalysts for methanol decomposition

The catalytic behaviors of Pd (1.4 wt.%) catalysts supported on CeO2-ZrO2 promoted with La2O3 were investigated for methanol decomposition. The measurements of inductively coupled plasma emission spectroscopy (ICP), N2 adsorption-desorption (BET), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR) and oxygen storage capacity (OSC) were used to characterize the properties of catalysts. The catalysts' activities were tested in a fixed bed continuous ...     

Co/CeO2 for ethanol steam reforming： effect of ceria morphology

Nanorods (NR) and nanoparticles (NP) of ceria were prepared by hydrothermal synthesis method and used as catalyst support to load cobalt for steam reforming of ethanol (SRE). The catalysts were characterized by using temperature programmed reduction, X-ray diffraction, transmission electron microscopy and thermal analysis techniques. CeO₂ NP had relatively smaller particle size and larger surface area, and CeO₂ NR could form more oxygen vacancies. For SRE reaction, Co/CeO₂ NP was more active and exhibited a little better anti-sintering ability, while Co/CeO₂ NR showed obviously better anti-carbon deposition ability. The larger surface area and higher dispersion of cobalt oxide resulted in the higher activity for Co/CeO₂ NP catalyst. Meanwhile, the stronger interaction between cobalt species and ceria was attributed to the better anti-sintering ability for Co/CeO₂ NP. The improvement of the anti-carbon deposition for Co/CeO₂ NR was owing to the generation of oxygen vacancies from the ceria nanorods.     

Synergistic effect between MnO and CeO2 in the physical mixture：Electronic interaction and NO oxidation activity

MnO and CeO2 powders were mechanically mixed by a spatula and by milling to obtain loose-contact and tight-contact mixed oxides,respectively.The monoxides and their physical mixtures were characterized by X-ray diffraction（XRD）,Brunauer-Emmett-Teller（BET）,X-ray photoelectron spectroscopy（XPS）,Raman,O2 temperature-programmed desorption（O2-TPD）,H2 temperature-programmed reduction（H2-TPR） and NO temperature-programmed oxidation（NO-TPO）.The MnOx-CeO2 solid solutions did not form without any calcination process.The oxidation state of manganese tended to increase while the ionic valence of cerium decreased in the mixed oxides,accompanied with the formation of oxygen vacancies.This long-ranged electronic interaction occured more significantly in the tight-contact mixture of MnO and CeO2.The formation of more Mn4＋and oxygen vacancies promoted the catalytic oxidation of NO in an oxygen-rich atmosphere.     

Surface reactive species on MnOx（0.4）-CeO2 catalysts towards soot oxidation assisted with pulse dielectric barrier discharge

MnOx(0.4)-CeO2 was investigated for soot oxidation assisted with a pulse dielectric barrier discharge(DBD).The catalysts were evaluated and characterized with TPO(temperature programmed oxidation),X-ray diffraction(XRD),Raman and X-ray photoelectron spectroscopy(XPS).The ignition temperature Ti for soot oxidation decreased from 240.8 to 216.4 oC with the increase of the pulse DBD frequencies from 50 to 400 Hz,lower than that of the case without pulse DBD present(253.4 oC).The results of XRD,Raman and XPS agreed well with the TPO activities of MnOx(0.4)-CeO2 towards soot oxidation.More solid solution of ceria and manganese,and surface reactive species including O2–,O– and Mn4+ were responsible for the enhancement of soot oxidation due to pulse DBD injection in the present study.For solid solution favors to the activation and transformation of those species,which are believed to be involved in the soot oxidation in a hybrid catalysis-plasma.     

Effects of oxygen defects on structure and properties of Sm0.5Sr0.5CoO3-δ annealed in different atmospheres

Samples of Sm0.5Sr0.5CoO3–δ were annealed in different atmospheres（Ar,N2,and O2） and temperatures（400 1200 oC）,and changes in their masses,structures,surface transport properties,optical properties,and oxygen nonstoichiometries were investigated using thermogravimetric（TG） analyses,X-ray diffraction（XRD） analyses,electrical conductivity measurements,reflection spectra measurements,and X-ray photoelectron spectroscopy,respectively.The TG analyses,performed in air and an N2 atmosphere,allowed us to determine the changes in the masses of the samples.The results of the XRD analyses elucidated the changes in the structure of the samples under different conditions.The XPS spectra and simulation data indicated that the number of oxygen defects generated in the samples depended on the temperature and atmosphere.At high temperatures,the surface conductivities and full-spectrum reflectivities of the samples decreased with an increase in the number of oxygen vacancies.In an oxidative atmosphere,the samples exhibited outstanding visible and near-infrared light absorption.Furthermore,the samples were highly sensitive to a reducing atmosphere at various temperatures.On the basis of the fact that the properties of Sm0.5Sr0.5CoO3–δ vary with the environment,it has potential use in high-temperature applications such as weather sensors.     

Preparation and photocatalytic activity of La^3＋ and Eu^3＋ co-doped TiO2 nanoparticles： photo-assisted degradation of methylene blue

Rare earth ions La³⁺ and Eu³⁺ co-doped TiO₂ photocatalyst (La-Eu/TiO₂) was prepared by sol-gel method, and characterized by various techniques such as X-ray diffraction (XRD), specific surface area and porosity (BET and BJH), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflectance spectroscopy (DRS) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of the La-Eu/TiO₂ was evaluated by the degradation of methylene blue (MB) under UV light irradiation. The catalyst had a relatively uniform particle diameter distribution in the range of 40–60 nm. When calcining at 600°C, the XRD patterns of La-Eu/TiO₂ indicated the anatase phase, while the XPS patterns showed the Ti⁴⁺, La³⁺ and Eu³⁺ ions existence. The DRS spectra showed red shift in the band-gap transition. The experimental results of MB degradation demonstrated that the photocatalytic activity of La-Eu/TiO₂ was significantly enhanced due to better separation of photogenerated electron-hole pairs.