Effects of Preparation Methods and Electronic States of the AuPd Bimetallic Nanoparticles on the Activity for Aerobic Oxidation of Alcohols

Correlations between nanostructure of AuPd active sites synthesized with different preparation methods and their catalytic activities for the oxidation of alcohols were investigated. The catalytic activity strongly depend on the morphology and Au/Pd molar ratio of the AuPd active site, these were attributed by the differences in preparation methods. The Au_Pd_-PVP/HT catalyst prepared with a simultaneous reduction method exhibited the highest activity for aerobic oxidation of alcohol; ex. TON = 395,700, TOF = 207,000 h^ for 1-phenylethanol oxidation.Characterizations with TEM, XPS, XAFS and other analytical techniques suggested that the highly active Au_Pd_-PVP/HT catalyst possessed uniform AuPd nanoalloys and the largest amount of electrons in Au 5d states. These results proposed that formation of the uniform AuPd nanoalloys allowed a big electron transfer from Pd to Au atoms, and which played an important factor for the significant activity of the Au_Pd_-PVP/HT

High Temperature Neutron Powder diffraction study of the Oxide Ion Conductor La_0.9Ga_0.1Mg_0.2O_2.85

Powder neutron diffraction data have been collected between room temperature and 1000 degrees C for the oxide ion conductor La0.9Sr0.1Ga0.8Mg0.2O2.85 and the undoped parent phase LaGaO3. In agreement with previous studies, refinement of the data for the undoped phase showed that the cell is orthorhombic (Pbnm) at room temperature and rhombohedral (R3c) between 250 and 1000 degrees C, The structure of the doped system La0.9Sr0.1Ga0.8 Mg0.2O2.85 is, however, significantly different from that of pure LaGaO3, The room temperature structure is monoclinic (I2/a), and there appear to be two phase transitions between 250 and 1000 degrees C: monoclinic (pseudo-orthorhombic) --&gt; monoclinic (pseudo-rhombohedral) --&gt; rhombohedral, Significant changes are also seen in the GaO6 octahedra on doping LaGaO3. In particular, the octahedra are substantially more distorted in the doped phase, The tilting of the octahedra is smaller for the doped phase and the degree of tilting is reduced as the temperature is raised. Possible correlation between the tilting of the octahedra and the activation energy for oxide ion conduction is presented, (C) 1998 Academic Press.</p

High Temperature Neutron Powder diffraction study of the Oxide Ion Conductor La_0.9Ga_0.1Mg_0.2O_2.85

Powder neutron diffraction data have been collected between room temperature and 1000 degrees C for the oxide ion conductor La0.9Sr0.1Ga0.8Mg0.2O2.85 and the undoped parent phase LaGaO3. In agreement with previous studies, refinement of the data for the undoped phase showed that the cell is orthorhombic (Pbnm) at room temperature and rhombohedral (R3c) between 250 and 1000 degrees C, The structure of the doped system La0.9Sr0.1Ga0.8 Mg0.2O2.85 is, however, significantly different from that of pure LaGaO3, The room temperature structure is monoclinic (I2/a), and there appear to be two phase transitions between 250 and 1000 degrees C: monoclinic (pseudo-orthorhombic) --&gt; monoclinic (pseudo-rhombohedral) --&gt; rhombohedral, Significant changes are also seen in the GaO6 octahedra on doping LaGaO3. In particular, the octahedra are substantially more distorted in the doped phase, The tilting of the octahedra is smaller for the doped phase and the degree of tilting is reduced as the temperature is raised. Possible correlation between the tilting of the octahedra and the activation energy for oxide ion conduction is presented, (C) 1998 Academic Press.</p

Research Update: Structural and transport properties of (Ca,La)FeAs2 single crystal

Structural and transport properties in the normal and superconducting states are investigated in a Ca0.8La0.2FeAs2 single crystal with Tc = 27 K, belonging to the newly discovered 112 family of iron based superconductors. The transport critical current density Jc for both field directions measured in a focused ion beam patterned microbridge reveals a weakly field dependent and low anisotropic behaviour with a low temperature value as high as Jc(B = 0) 3c 105 A/cm2. This demonstrates not only bulk superconductivity but also the potential of 112 superconductors towards applications. Interestingly, this superconducting compound undergoes a structural transition below 100 K which is evidenced by temperature-dependent X-ray diffraction measurements. Data analysis of Hall resistance and magnetoresistivity indicate that magnetotransport properties are largely dominated by an electron band, with a change of regime observed in correspondence of the onset of a structural transition. In the low temperature regime, the contribution of a hole band to transport is suggested, possibly playing a role in determining the superconducting state

A Note on Environmental Awareness and Cross-Border Pollution

Considering a Nash equilibrium in which a developed country chooses the amount of foreign aid and a developing country sets the emission tax rate and the proportion of the received aid allocated to public abatement of pollution, it is shown that an increase in the recipient country’s environmental awareness will reduce the level of cross-border pollution and benefits the donor though its foreign aid is increased. Copyright Springer 2005cross-border pollution, emission tax, environmental awareness, foreign aid, public abatement of pollution,