Abnormality of Magnetic Behavior and Resistivity of La_(0.7-x)Dy_x Sr_(0.3)MnO_3 (0.00≤x≤0.30)System at Low Temperature

By measuring M-T curves, ρ-T curves and MR-T curves of the samples under different temperatures, the influence of Dy doping （0.00 ≤ x ≤0.30） on the magnetic and electric properties of La0.7-xDyxSr0.3MnO3 has been studied. The experimental results show that, with the increase of the Dy content, the system undergoes a transition from long range ferromagnetic order to the cluster-spin glass state and further to antiferromagnetic order. For the samples with x=0.20 and 0.30, their magnetic behaviors are abnormal at low temperature, and their resistivities at low temperature have a minimum value. These peculiar phenomena not only come from the lattice effect induced by doping, but also from extra magnetic coupling induced by doping.

Comparative Study on Oxidative Desulfurization of FCC Gasoline by Ce^(4+) Compound and H_2O_2

This article describes two kinds of model oil samples made of a benzothiophene/octane mixture and a 2-me- thylthiophene/octane mixture. Furthermore, this paper investigates the oxidative desulfurization selectivity and reaction efficiency when Ce4+ compound and H2O2 having identical electron equivalent weight were used as oxidants. The test re- sults showed that the two kinds of oxidants were more effective to remove benzothiophene in the model oil samples. For oxidative desulfurization of 2-methylthiophene, Ce4+ compound was obviously superior than H2O2. This paper by means of quantum chemistry analyses elaborates the complex formed between Ce4+ species and 2-methylthiophene and FT-IR spec- trograms of model oil samples before and after oxidation by Ce4+ compound and H2O2, respectively. The results demonstrat- ed that Ce4+ compound could remove sulfur compounds not only through oxidation reaction but also through complexation reaction.

Li_2O_2 oxidation: the charging reaction in the aprotic Li-O_2 batteries

Aprotic Li-O2 battery has attracted a great deal of interest because of its high theoretical energy density that is far beyond what the best Li-ion technologies can achieve.However, the present Li-O2 batteries suffer from the low energy efficiency that is limited mainly by the high overpotentials required to re-oxidize Li2O2, the discharge product. Over the past few years, considerable research efforts have been devoted to the understanding of the Li2O2 oxidation reactions. Here, we summarize the results obtained from the fundamental study of the Li2O2 oxidation, including its morphology, reaction route, kinetics, the initial location upon oxidation and the charge transport within Li2O2. A better mechanistic understanding of the Li2O2 oxidation reaction will provide a solid foundation for the realization of practical Li-O2 cells with a higher energy efficiency.

Holey platinum nanotubes for ethanol electrochemical reforming in aqueous solution

The catalytic/electrocatalytic performance of platinum(Pt)nanostructures highly relates to their morphology.Herein,we propose a facile self-template pyrolysis strategy at high temperature to synthesize one-dimensionally holey Pt nanotubes(Pt-hNTs)using Pt^(Ⅱ)-dimethylglyoxime complex(Pt^(Ⅱ)-DMG)nanorods as the reaction precursor.The coordination capability of DMG results in the generation of Pt^(Ⅱ)-DMG nanorods,whereas the reducibility of DMG at high temperature leads to the reduction of Pt^(Ⅱ)species in Pt^(Ⅱ)-DMG nanorods.During the reaction process,the inside-out Ostwald ripening phenomenon leads to the hollow morphology of Pt-hNTs.Benefiting from the physical characteristics of hollow and holey structure,Pt-hNTs with clean surface show superior electroactivity and durability for catalyzing ethanol electrooxidation as well as hydrogen evolution reaction in alkaline media.Under optimized experimental conditions,the constructed symmetric Pt-hNTs||Pt-hNTs ethanol electrolyzer only requires an electrolysis voltage of 0.40 V to achieve the electrochemical hydrogen production,demonstrating a highly energy saving strategy relative to traditional water electrolysis.