Advanced Materials Research Vol. 827

Abstract: The photocatalytic activity of eosin-sensitized TiO₂ nanoparticles on photocatalytic degradation rate (PDR) of methyl orange under sunlight irradiation was studied. The influential factors on the degradation, such as eosin concentration, TiO₂ dosage, sensitization time and sensitization temperature were also investigated. The results show that: The performance of TiO₂ nanoparticles for PDR of methyl orange has been improved obviously for eosin sensitizing. The PDR of methyl orange reached 45.28% under the conditions of eosin concentration of 20mg/L, TiO₂ dosage of 0.5000g/L, sensitization time of 24h and sensitization temperature of 20°C.

Abstract: TRIP (Transformation induced plasticity) steel has a good combination of high strength and high plasticity which depend on the micro phase transformation and staking fault development greatly. C atom was typical alloying agent of austenite and plays an important role in austenite behavior, especially for staking fault nucleation. As a micro materials behavior, molecular dynamics simulation was carried out to discuss the effect of C atom on the staking fault nucleation. From the simulation result we can find that carbon influence the staking fault nucleation greatly, with the increasing of the number of C atoms, strain for staking fault form decreased, system with 4 C atoms staking fault formed when strain was 7.5% and for system without C atoms there are no staking fault with local tension strain up to 10%. Under the same deformation, stacking fault distribution was uniform for the system with 1 carbon and become uneven with the increasing of the C atom.

Abstract: The optical properties of Cu-poor CuIn_1-xGa_xSe₂ thin films with different gallium contents grown by co-evaporated technique were studied. Measurements of photoluminescence and photoreflectance were performed on the samples. The photoluminescence and photoreflectance emission peaks observed around 1.1 eV are attributed to donor-acceptor pair luminescence. These donor-acceptor pair emissions are considered to originate from relatively shallow acceptor and donor energy levels. With increasing gallium content, the emission peaks shift towards higher levels of photon energy, and the linewidths of the luminescence spectra for the samples become wider, which we attributes to the greater statistical disorder between indium and gallium. Moreover, the conversion efficiency of the CuIn_1-xGa_xSe₂-based solar cells is obtained. The measured results coincide with the inference given by the photoluminescence spectra.

Abstract: on doping is an effective means to improve the performance of LiFePO₄ material. In the present study, composites LiFe (PO₄)_(1-x/3)F_x/C (x=0.00,0.02,0.04,0.06,0.08,0.10) were synthesized by carbothermal reduction method. The as-synthesized samples were characterized by X-ray diffraction and scanning electron microscope, and their electrochemical performances were investigated by constant current charge-discharge experiment. The results indicated that the low concentration F dopant did not affect the structure of LiFePO₄ but considerable improved its electrochemical performances. The LiFe (PO₄)_0.98F_0.06/C materials showed better electrochemical performances than LiFePO₄/C. At 0.2 C discharging rate, the LiFe (PO₄)_0.98F_0.06/C materials was capable of delivering reversible specific capacity of 165.1 mAh/g, with fairly stable cycleability. The excellent performance indicates that this mix-doped composite was a very promising cathode material for lithium ion batteries.

Abstract: The CuZnFeZrO₂ catalysts were synthesized by co-precipitation method.,and then used to synthesize different content of K₂O modified CuZnFeZrO₂ catalysts by deposition-precipitation method.Hydrogenation of CO₂ to higher alcohols over (K₂O)_x/CuZnFeZrO₂ catalysts were investigated at 523 K,3.0 MPa and 3000 h^-1.These catalysts were characterized by X-ray diffraction (XRD),temperature programmed reduction of H₂ (H₂-TPR),and temperature-programmed desorption of CO₂ (CO₂-TPD).The results showed the addition of an appropriate amount of Potassium to the CuZnZrO₂ catalysts improved catalytic activity ,the space time yield (STY) and C²⁺OH selectivity. When the Fe content is 5% best, at this time the space time yield of selectivity and alcohol of C²⁺ alcohol reaches the maximum value, this time space and time conversion rate is 0.32g/ml·h.

Abstract: Fast pyrolysis of biomass to produce bio-oil is an important technology to utilize lignocellulosic biomass, because the liquid bio-oil is regarded as a promising candidate of petroleum fuels. However, bio-oil is a low-grade liquid fuel, and required to be upgraded before it can be directly utilized in existing thermal devices. Catalytic cracking is an effective way to upgrade bio-oil, which can be performed either on the liquid bio-oil or the pyrolysis vapors. Various catalysts have been prepared and used for catalytic cracking, and they exhibited different catalytic capabilities. This paper will review the recent progress of the catalytic cracking of liquid bio-oil or pyrolysis vapors.

Abstract: The electrochemical degradation of tricyclazole (TC) in aqueous solution on Ti/SnO₂Sb/PbO₂ anodes was investigated. The degradation efficiency and mineralization rate was studied. Kinetic analyses indicated that the electrochemical degradation followed a pseudo-first-order reaction. The mineralization intermediates were analyzed by chromatographic techniques. Finally, a pathway for electrochemical degradation of TC in aqueous medium was proposed.

Abstract: TiO₂ nanocrystals were synthesized from Titanium Tetraisopropoxide in H₂O₂ solution, and utilized as photocatalysts for degradation of humic acid in aqueous solution. The highly pure TiO₂ nanocrystals were obtained by excluding the use of inorganic acids that might consequently cause contamination of active catalytic surface sites of the nanocrystals by Cl^-, NO₃^- and SO₄^2-. Particle size and crystallinity of the nanocrystals were increased with progressing the refluxing time 1 ~ 9 h at 120°C in an oil bath. By varying H₂O₂/Ti = 5.5 ~ 55, the crystalline phase of anatase/rutile ratio of the nanocrystals was controllable. The photocatalytic properties of the nanocrystals were strongly dependent upon the crystallinity and particle size. The DOC removal of humic acid was most effective for the nanocrystals prepared at H₂O₂/Ti= 5.5 due to the mixed crystalline phase of anatase/rutile and the increased surface area by smaller particle size. The decreases of UV₂₅₄ absorbance of HAs solutions were much faster than those of DOC, and not so dependent upon the variations of TiO₂ nanocrystals.

Abstract: Most of the photovoltaic industry uses wafer of single-crystal and poly-crystal silicon as a material of their photovoltaic (PV) modules. However, the cost of these modules is high due to the material and processing cost. Cuprous oxides (Cu2O) have several features that suitable for future photovoltaic applications. Cu2O can be prepared with simple methods at very low cost. Cu2O p-n homojunction solar cell is a device that converts sunlight to electrical energy, consists of two similar materials for its p-n junction, which is Cu2O. The p-type and n-type of Cu2O thin films are then fabricated to produce solar cells. Other layers aluminium and glass substrate coated with indium tin oxide (ITO) need to be added as a contact for electrons movement. In this study, p-type Cu2O, n-type Cu2O and p-n junction are prepared in order to become accustomed for solar cell applications. To achieve the optimum deposition conditions, p-n junction solar cell is prepared by two-steps electrochemical deposition process. The result from x-ray diffraction (XRD) shows that the peak is dominated by CuO (1, 1, 1). P-n junction is in between the p-type and n-type of Cu2O layer. Al has the thickness of 427.5nm. The second and the third layer are p and n type of Cu2O, which have the thickness of 106.9nm and 92.3nm, respectively. Finally the thickness of ITO layer is 131.1nm.An absorption experiment at AM1 light is performed in order to get the I-V curves, and in fact, to study the electrical solar cells p-n homojunction. Based on I-V curve test, the level of energy conversion of cell is 0.00141% with fill factor, FF 0.94813 which proved that Cu2O p-n homojunction solar cell can be fabricated and produced at very low cost and well function.