Advanced Materials Research Vol. 800

Abstract: Effects of solid solution treatment and rolling treatment on microstructure and electrochemical properties of Al-Ga-Mg-Mn-Bi anode alloy were investigated by means of SEM and electrochemical measurements. The results show that after solid solution treatment the microstructure segregation of the as-cast alloy was reduced, the hydrogen evolution was restrained, the corrosion resistance was increased. The open circuit potential moves towards negative after solid solution treatment. Rolling treatment had little impact on the alloy. The effects of solid solution treatment were superior to rolling treatment.

Abstract: An investigation was carried out into temperature distribution in 3KA rare earth electrolytic cell and changes of products quality in neodymium electrolysis from a factory in China, The results show that the different temperature distributions have direct effects on the neodymium products quality. In same production cycle, the cell voltage of electrolytic cell is stable and curre rocessing before discharging bascially stays the same; In different cycles, temperature distribution not always alike, mainly reflected in lateral distribution of temperature in electrolytic cell, one form is temperature gradually increased from cathode to anode, and the anode temperature is highest; another is temperature declined then elevated again, anode temperature is slightly higher than the temperature of cathode. The second distribution is benefit for improve the quality of products.

Abstract: Li_0.96Na_0.04Ni_1/3Co_1/3Mn_1/3O₂ with CTAB as additive was synthesized. X-ray diffraction pattern reveals the product of the material with CTAB is pure phase. Scanning electron microscopy shows that the powders are average of 200 nm. Electrochemical test shows it in terms of high initial discharge capacity (175.6 mAhg^-1) and exhibits good cycle performance with the capacity retention of 93.39 % after 90 cycles compared to the material has no additive (167.6 mAhg^-1 and 71.18 %) at 0.1 C rate. Therefore, CTAB as additive should improve the performance of Li_0.96Na_0.04Ni_1/3Co_1/3Mn_1/3O₂ cathode material.

Abstract: This essay describes the findings of generating the electrode composite of polyaniline/activated carbon fiber ( PANI/ACF) by repeatedly immersing eigenstate PANI into the solution of NMP and CHCl₃ added with VC. A samples surface profile and structure were represented using SEM and FT-IR. Thereafter the composite was assembled into a super capacitor, electrochemical performances of which were then tested through cyclic voltammetry (CV). The result showed that the specific capacitance of this composite is up to 531.75F/g in the solution of 6 mol·L^-1 KOH.

Abstract: In order to realize the optimization of pyrolysis process, the pyrolysis characteristics and kinetics of common agriculture and forestry biomass were studied. Four kinds of biomass were chosen as experiment materials for thermo-gravimetric experiment. The Characteristics of biomass pyrolysis was studied by defining a new evaluation methodology. The method of Coats-Redfern was used to analyze pyrolysis kinetics of biomass pyrolysis process. The results of research show that the pyrolysis process of biomass can be divided into three stages, including drying and preheating, fast pyrolysis and slow decomposition of residue. The activation energy of pyrolysis reaction of biomass during the low temperature stage is higher than that of the high temperature stage. The values of the activation energy and pre-exponential factor are increasing with the increase of heating rate. The pyrolysis of biomass in the main pyrolysis zone can be effectively described by using the kinetic model n=2. The heating rate of 15K/min and temperature of 500°C can improve the reaction rate, and it helps to reduce energy consumption of the reaction.

Abstract: The thermal behavior and thermal decomposition kinetic parameters of podophyllotoxin (PPT) and 4-demethypodophyllotoxin (DMPPT) in a temperature-programmed mode have been investigated by means of DSC and TG-DTG. The kinetic model functions in differential and integral forms of the thermal decomposition reactions mentioned above for leading stage were established. The kinetic parameters of the apparent activation energy E_a and per-exponential factor A were obtained from analysis of the TG-DTG curves by integral and differential methods. The most probable kinetic model function of both decomposition reactions in differential form was (1-α) ². The values of E_a indicated that the reactivity of PPT was higher than that of DMPPT in the thermal decomposition reaction. The values of the entropy of activation ΔS^≠, enthalpy of activation ΔH^≠ and free energy of activation ΔG^≠ of the reactions were estimated.

Abstract: In this work, graphene nanosheets (GNSs) were prepared by the thermal pyrolysis of graphene oxide (GO) at 900 °C for 3 h, and their electrochemical performances as anode materials for lithium ion batteries (LIBs) were also investigated. TEM and SEM images clearly showed that the as-prepared GNSs had a transparent two-dimensional (2D) structure with 5~10 multilayers. The other experimental results (XRD, Raman, TG and FT-IR) confirmed the successful synthesis of GNSs. Electrochemical measurements revealed that GNSs had an initial discharge capacity of 1276 mAh g^-1 and still remained 723 mAh g^-1 after 50 cycles, indicating that the as-prepared GNSs shows a great potential as anode materials for LIBs.

Abstract: Platinum nanoparticles deposited on noncovalent functionalized graphene modified by 1, 10-Phenanthroline were prepared by ethylene glycol reduction process under the assistance of the microwave. The structure, morphology, composition and surface properties of the as-prepared catalysts Pt/graphene are characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). The results showed that platinum particles were uniformly dispersed on the surface of 1,10-Phenanthroline noncovalent modified graphene, and the particle size was about 1nm. Cyclic voltammetry(CV), linear sweep voltammetry(LSV) and Tafel curves were used to test the oxygen reduction electrode. Through electro-chemical testing, we found that the graphene based electrocatalysts significantly increased the oxygen reduction reaction(ORR) of aluminum-air batteries. This result illustrated that Pt nanoparticles deposited on noncovalent functionalized graphene could be used as an efficient catalyst material for aluminum-air batteries with the feature of much increased catalytic activity.

Abstract: The electrochemical copolymerization of poly (N-vinylcarbazole) (PVK) and 3-methylthiophene (3MeT) was successfully achieved by direct anodic oxidation of monomer mixtures in dichloromethane containing 10% boron trifluoride diethyl etherate (BFEE) (by volume) and Bu₄NBF₄ (0.05 M). The structure of the copolymer was characterized by infrared spectroscopy. Fluorescence spectral studies demonstrated that poly (PVK-co-3MeT) has high fluorescent property with its maximum emission at near 410 nm.

Abstract: In this study, the Box–Behnken design matrix and response surface methodology (RSM) have been applied in the experiments to evaluate the interactive effects of four most important operating variables: pH (2.0–4.0), temperature (30–40°C )，iron/carbon ratio（1/2–3/2）and iron carbon amounts (2-4) on the removal of Pb (II), Cu(II)，Zn (II) and Cd (II) ions in acid mine drainage with micro-electrolysis (ME) . The total 29 experiments were conducted in the present study for the construction of a quadratic model. The independent variables have significant value 0.0001, which indicates the importance of these variables in the ME process. The values of “Prob > F” less than 0.0500 indicate that model terms are significant for the removal of Cr (VI), Ni (II) and Zn (II) ions. The regression equation coefficients were calculated and the data fitted to a second-order polynomial equation for removal of Pb (II), Cu(II)，Zn (II) and Cd (II) ions with ME.