Advanced Materials Research Vols. 953-954

Abstract: Graphene/Ag nanoparticles (GAg) were fabricated via a facile method, employing graphite oxide as a precursor of graphene (GNS), AgNO₃ as a precursor of Ag nanoparticles, and sodium citrate as a reducing and stabilizing agent. We synthesized three kinds of GAg and denominated as GAg-1、GAg-2 and GAg-3. Graphene exhibits good electron conductivity, thermal conductivity, chemical stability and mechanical strength. We investigated the effect of inserting Graphene/Ag nanoparticles between hole transfer layer (HTL) of poly (ethylene dioxythiophene) (PEDOT)-polystyrene sulfonic acid (PSS) (PEDOT:PSS) and active layer (P3HT:PCBM =1:1 weight ratio) on the characteristics of polymer solar cell. The cell structure was ITO/PEDOT:PSS/GAg/P3HT:PCBM/Ca/Al. The concentration of Graphene/Ag nanoparticles solution was 2.0 mg/ml and the GAg nanoparticles layer was coated by spin-coating at 6000 rpm. We studied the effect of GAg layer addition on the photovoltaic performance. We used the UV-Vis, SPM, FE-SEM and solar simulator to measure the absorbance, roughness, surface morphology, and power conversion efficiency (PCE), respectively. From these results, we found that the short circuit current density (J_sc), fill factor (FF) and PCE of the cells with GNS or GAg were always higher than those of cell without GNS or GAg. The cell with GAg-2 had the highest short circuit current density (J_sc) of 9.14 mA/cm², an increase of 28.4%, highest fill factor (FF) of 0.65, an increase of 32.7% and highest PCE of 3.82%, an increase of 71.3% when compared to standard device with active layer of P3HT:PCBM =1:1. These improvements were due to the high carrier mobility of graphene.

Abstract: The rock thermal conductivity of coal measure strata in Huainan-Huaibei Coalfield ranges from 0.37 W/mK to 4.36W/mK and the average value is 2.54W/mK. The thermal conductivity closely relates to lithology,buried depth,stratigraphic age and density, the thermal conductivity of sandstone is generally greater than the one of mudstone and coal, and thermal conductivity and depth, density all show the positive correlation relationship; The differences of thermal conductivity of rocks have greater effects on the Geothermal field characteristics, unconsolidated layers and coal seams with poor heat conductivity tend to cause the abnormal ground temperature.

Abstract: In the making process of LiFePO₄ positive electrode film, part of electrical carbon was replaced by some carbon nanotubes (CNTs), its electrochemical performance was improved greatly. nanoLiFePO₄ batteries’ temperature performance were tested at different ambient temperature, at-40 °C the discharge capacity is about the 25°C’s 47.1%, While the ordinary LiFePO₄ battery is only 37.5%; Superior electrochemical performance of the battery cell is mainly due to the improvement of the electrical properties, in order to ensure the service life of the battery itself, the working temperature should be controlled between 20°Cand 50°C.

Abstract: The Sn-Ge metal composite powder was obtained by reduction of the SnGeO₃. The XRD and SEM analysis of Sn-Ge were completed. The simulation battery was prepared by using the Sn-Ge as lithium ion battery anode material, and its electrochemical properties were characterized. The results indicate that the SnGeO₃ was reduced at 723K to generate the Sn-Ge composite powder instead of the alloy. The first embedding lithium capacity (discharge capacity) was 625 mAh·g^-1, the first taking off lithium capacity (charge capacity) was 590 mAh·g^-1 for the simulation battery. The capacity gradually decreased with the charge-discharge cycle number increasing, and the discharge capacity corresponded to 88% of the initial discharge capacity, and the charge capacity corresponded to 89% of the initial charge capacity at 20^th week. The Sn-Ge composite powder can be used as the lithium ion battery anode material due to possessing embedding / taking off lithium capacity.

Abstract: The Ni²⁺ doped TiO₂ film (Ni-TiO₂) was produced in-situ on the pure Ti plate substrate in the electrolyte solution of Na₃PO₄ containing of Ni (Ac)₂ by micro-arc oxidation process (MAO). The effect of Ni (Ac)₂ content on structure and H₂ production activity of Ni-TiO₂ had been investigated. It was found that the characteristic peak (101) of anatase phase for Ni-TiO₂ decreased gradually without the peak of Ni and the red shift of its absorption edge appeared with the increase of Ni (Ac)₂ content. It was showed from experimental results that the highest H₂ production rate was 0.31 μmol/ h·cm² over the above-prepared Ni-TiO₂ at Ni (Ac)₂ content of 5 g/L.

Abstract: The Raman spectra of polystalline Er₂O₃ films on Si (001) substrates annealed at different temperatures in O₂ atmosphere were investigated. Seven Raman lines are identified in annealed Er₂O₃ films on Si (001) substrates. Two broad peaks larger than 600 cm^-1 are detected, and their origination is discussed. Raman spectroscopy is proved to be a simple and sensitive method to characterize the structures of Er₂O₃ films on Si substrates.

Abstract: The structural morphology, arrangement of the nanocrystalline particles, porosity factor, surface state, crystalline phase and specific area of photoelectrode film have great influence on photoelectric performance of dye sensitized solar cells (DSSCs). At present, using TiO₂ as the photoelectrode in the DSSC material has achieved very good photoelectric conversion efficiency. In this paper, the plating method is adopted to directly deposited the titanium coating on the conductive glass substrate, oxidizing the surface of titanium film, so that it is generated on the surface of titanium dioxide oxidation layer. Making it as the DSSC photoelectrode, obtained relative high photoelectric conversion efficiency.

Abstract: Although the effect of phosphate on photocatalytic activity of TiO₂ is extensively investigated, its effect on the photoelectrocatalytic activity of TiO₂ electrode is not clear. The effect of phosphate on photoelectrocatalytic oxidation of water and organics on the TiO₂ electrode were investigated in this study. Phosphate has a sophisticated influence on the photoelectrocatalytic oxidation of water on TiO₂ electrode. The photoelectrocatalytic oxidation of water was inhibited at the low phosphate concentration (<5 μM) while improved at the high concentration. However, phosphate has an adverse influence on the photoelectrocatalytic oxidation of whether the strong or not the weak adsorption organics on the TiO₂ electrode, which is different from its effect on photocatalytic process of organics on the TiO₂ slurry, in which the photocatalytic oxidation of the weak adsorption organics is enhanced. However, phosphate can improve the linear concentration range of organics, especially strong adsorption organics (e.g. KHP, 0-333 μM for without phosphate to 0-500 μM for the with 1 M phosphate). Moreover, it is unanimously consent that phosphate has a very strong acid-base buffer capacity. These properties provide an excellent potential for phosphate application during the detection of practical samples, especially the acid and/or base samples.

Abstract: The objective of this study was to investigate the toxicity of Na⁺ and K⁺ ions on performance of upflow anaerobic sludge blanket (UASB) system. Three laboratory-scale UASB reactors, 15.8 - l working volume, were employed with 1 reactor operated as control. They were loaded at organic loading rate (OLR) of 5 kg COD/(m³-d), treating synthetic wastewater with COD concentration ~ 5000 mg/l. Na⁺ and K⁺ ions were added in the range of 1010 - 7180 and 41 - 7320 mg/l, respectively. No toxicity was observed at influent Na⁺ and K⁺ concentrations up to 3340 and 2750 mg/l, respectively. Slight inhibitions on COD removal were founded at Na⁺ and K⁺ concentrations of 4610 and 3920 mg/l, respectively, but moderate effect on biogas production had occurred. When Na⁺ and K⁺ concentrations were increased to 7180 and 7320 mg/l, respectively, strong inhibitions were observed with COD removal dropped to 45.5 and 48.8 %, respectively. Ratios of biogas productions, as compared to the control reactor, were dropped to 0.31 and 0.32, respectively. Increasing cation concentrations had more detrimental effect on biogas production than COD removal.

Abstract: Microencapsulated phase change materials (MPCM) slurries with high heat transfer and great latent heat can serve as both the heat transfer fluids and energy storage medias. Studies showed that the effective specific heat and heat transfer rate increased by 28.1% and 23.6% respectively as using MPCM slurries. The rheological behavior of slurries do not change as adding MPCM with low concentration, can be characterized by Newtonian fluid feature with mass fraction <0.25. MPCM particles have flow drag reduction effect under turbulent situation, which was applied to building energy efficiency and refrigeration, obtained remarkable energy conservation effect.