Advanced Materials Research Vols. 953-954

Abstract: It is well-known that TiO₂ is an environmental benign photocatalyst which can be used to decompose harmful organic compounds. Recently, many studies are concentrated on the purification of industrial wastewater due to the requirement of environmental protection. In present study, TiO₂ nanomaterials supported by fine zeolite particles have been used as the photocatalyst to purify the oily wastewater. It has been found that the oil concentration in the modulated water can be reduced significantly and rapidly under the action of photocatalytic degradation and the ultraviolet light radiation. After 80 minutes, oil concentration in the modulated water can be reduced by more than 80%. The results suggest that TiO₂ nanomaterials supported by fine zeolite particles are effective material for purification of oily wastewater. In addition, the present results show that the efficiency of water purification can be significantly increased by use of mechanical stirring during the photocatalytic degradation process.

Abstract: Olivine-type LiFePO4 and crystal structure LiMn2O4 or LiNi0.5Mn1.5O4 are promising cathode materials for electric vehicles (EVs) applications. To find more appropriate electrolyte systems to exert the perfect electrochemical performance of LiFePO₄, LiMn₂O₄ and LiNi_0.5Mn_1.5O₄ cathodes, the electrochemical performances of LiBOB-ethylene carbonate (EC)/ethyl methyl carbonate (EMC)/diethyl carbonate (DEC) electrolyte are investigated in this paper. In LiFePO₄/Li, LiMn₂O₄/Li and LiNi_0.5Mn_1.5O₄/Li cells, this novel electrolyte exhibits several advantages, such as stable cycle performance and good rate performance. It suggests that LiBOB-EC/EMC/DEC electrolyte has good compatibility with the three kinds of cathodes, and would be an attractive electrolyte for lithium-ion batteries based upon LiFePO₄, LiMn₂O₄ and LiNi_0.5Mn_1.5O₄ cathodes.

Abstract: This paper presents gasification kinetic parameters generated for Japanese lignite coal char reacting with carbon dioxide and the method for obtaining them. The experiments were conducted in a PTGA at atmospheric pressure within a temperature range of 1148K-1223K, and a mass spectrometer (MS) is coupled with PTGA to obtain the concentrations of product gas. The experiments were carried out with isothermal method, and kinetic parameters were determined through the analysis of the weight changes of coal char and the concentrations of products respectively. The effect of CO₂ partial pressure on reaction rate was analyzed by n^th order rate equation. It was found that the activation energy of char-CO₂ reaction obtained from weight loss curve and product concentrations were 187.9kJ/mol and 187.0kJ/mol respectively, and the reaction order n were 0.24 and 0.222, proving MS a feasible method for kinetics research. Through the comparison, the method to obtain the kinetic data by concentrations of gas products was determined, and a more clear understanding of the gasification process was established.

Abstract: Abstract. Lithium bis(oxalato)borate (LiBOB) is a promising salt for lithium ion batteries. The electrochemical behaviors of tetramethylene sulfone (TMS) / dimethyl sulfite (DMS) with different volume ratios of 1:2, 1:1, and 2:1 with 0.7 mol L-1 LiBOB salt are investigate in this work. Although the proportion of different solvents show different electrochemical performance, both of the LiBOB-based electrolytes show high oxidation potentials (> 5.5 V), and excellent film-forming characteristics.

Abstract: Aimed at improving the utilization of pulverized coal, high-temperature heat pipe technology was introduced into lignite carbonization.Under the design of power of 10kw semi-industrial pulverized coal carbonization test equipment, Fugu lignite coal as raw material to investigate the operating characteristics of the device and carbonization characteristics. Experimental result shows that the high temperature heat pipes heat steadily and meet the temperature requirement of low-temperature carbonization. With the extension of the holding time, the semi-coke fixed carbon content increasing, but volatile matter vice versa, however, holding time above 60 minutes, the effect of carbonization is not obvious, and the best carbonization time is 30 ~ 60 minutes. The length of the holding time has little effect on gas composition, the content of H₂ and CH₄ are relatively higher than the rest gas, (H₂ + CH₄) gas accounted for 70% of the total, the heating value remains at 18.76 ~ 19.22MJ/m³, belongs to medium-high value gas, could provide for industrial and civilian use.

Abstract: α-MnO₂ nanowire was prepared by hydrothermal method. The structure of as-prepared manganese oxide demonstrated tetragonal crystalline in X-ray diffraction pattern. Scan electron microscopy (SEM) and Transmission electron microscopy (TEM) revealed the nanowire morphology of as-prepared α-MnO₂. The band gap of α-MnO₂ was estimated at about 2.06 eV via UV-vis spectrum. As the electrode active material for supercapacitor, the electrochemical specific capacitance of α-MnO₂ nanowire achieved 156.5 F/g, which possessed typical capacitive behaviors and good cycling stabilities. Based on the preferable electrochemical performances, as-synthesized α-MnO₂ nanowire may be a potential alternative as electrode material for supercapacitor.

Abstract: The Ag-assisted electroless etching of p-type silicon substrate in HF/H₂O₂ solution at room temperature was investigated. In this work, the effects of HF, H₂O₂ and their volume ratio on morphology and growth of p-type silicon substrate surface by using metal assisted etching were investigated in order to produce a highly efficient antireflecting structure. The Ag metal particles were deposited onto Si wafer by electroless deposition from a metal salt solution including HF. The experimental results show that the growth rate and morphology of the pores formed on the Ag metalized Si surfaces are strongly dependent on the volume ratio of HF and H₂O₂.

Abstract: Lthium difluoro (sulfato) borate (LiBF₂SO₄) is a prospecting salt for electrolyte of lithium-ion batteries. The effect of LiBF₂SO₄ salt on conductivity, charge-discharge capacities, temperature performance, cycling life and storage life at 60 °C is investigated. In graphite half cells at 60 °C, LiBF₂SO₄-ethylene carbonate (EC)/ dimethyl carbonate (DMC) electrolyte favourably facilitates the formation of a thermal stable, effective and conductive interface film on the surface of carbonaceous anode. Besides, in LiCoO₂ half cells at 60 °C, the electrolyte containing the novel salt exerts several advantages, such as stable cycling performance, and good capacity retention performance.

Abstract: Batch-type base catalysis is currently the main process used for biodiesel production. Methods to reduce costs, improve capacity and decrease the emission of pollutants in the production of biodiesel are of great significance. This paper studied the reaction conditions for fatty acid methyl ester (FAME, referred to as biodiesel) production through the transesterification of soybean oil with methanol in the presence of Mg-Al hydrotalcite/γ-Al₂O₃ as a fixed-bed catalyst. The influences of the methanol-oil ratio, space velocity, reaction temperature and pressure on product conversion were investigated. The results indicated that the optimum reaction conditions were as follows: methanol/oil ratio of 21:1, space velocity of 0.5 h^-1, reaction temperature of 340°C, and reaction pressure of 2 MPa. Under these conditions, the one stage conversion rate was 80% and the lifetime of the catalyst was 220 h. The catalyst can process raw materials with high total acid numbers using two stages project.

Abstract: Nano-sized LiNi0.5Mn1.5O4 spines is prepared by a sol-gel reaction at 800 °C in air. Scanning electron microscopic (SEM) image indicates that LiNi0.5Mn1.5O4 has cubic spinel structure with small and homogeneous particles (about 300 nm). Electrochemical test shows that the prepared LiNi0.5Mn1.5O4 delivers up to 125 mAh g− 1at 0.2 C, and the capacity retains 110 mAh g− 1 at 0.5 C after 50 cycles.