Applied Chemical Engineering (Transferred)

Abstract Based on the existing experiment, Gaussian 03 package to study the adsorption microscopic behavior between thiophene molecules and three transition metals M = (Mo, Pd, Sn) were used, which combine with the quantum chemistry method and the genecp basis set. It is showed there are many different molecular adsorption patterns between the different transition metal atoms thiophene. The transition metal Mo is given more priority to occur the β and θ adsorbing model, and the decreased energy was 328.795 kJ/mol and 327.868 kJ/mol respectively. Transition metal Pd is given more priority to occur the δ adsorbing model, and the decreased energy as high as 380.654 kJ/mol; transition metal Sn is given more priority to occur the α and δ adsorbing model, and the decreased energy was 272.514 and 512.130 kJ/mol, respectively. The correction of zero energy should be considered in the calculation of adsorption energy. B3LYP method is more advantage about optimization and energy calculation.

Abstract Zinc ferrite/N-doped graphene catalysts were synthesized by hydrothermal reaction. The synthesized materials were characterized by XRD, TEM, Raman and UV-VIS-DRS. We explored the photocatalytic simultaneous removal of nitrite and ammonia via zinc ferrite/N-doped graphene as the photocatalyst. The effects of Ph, amount of catalyst, N-doped graphene content, and initial concentration of ammonia on photocatalytic removal of nitrite and ammonia were examined. The results show that the removal ratio of nitrite–N and ammonia–N is 90.95% and 62.84% respectively， when the dosage of ZnFe₂O₄/NG (NG 5.0 wt%) is 1.5 g·L^-1 and the initial concentrations of nitrite–N 50 mg·L^-1，ammonia–N 100 mg·L^-1 with pH 9.5 under anaerobic conditions upon white light irradiation for 3 h. After the solution is aerated for 30 mins and irradiated for 10 h under aerobic conditions, the removal ratios of nitrite–N，ammonia–N and total nitrogen are 92.04%, 89.44% and 90.31% respectively. The complete removal of nigrogen is done.

Abstract Nickel-manganese oxides were studied for selective catalytic reduction of NO by XRD，H₂-TPR and N₂ adsorption-desorption. The study was found that the catalyst Ni_0.4 Mn_0.6O_x showed the best SCR activity，the reasons may be as follows: Ni_0.4Mn_0.6O_x catalyst showed the optimal synergistic effect between nickel and manganese and appropriate redox ability, which were conducive to NH₃ under the condition of low temperature catalytic reduction of NO．

Abstract The passivation layer of solar cells directly affects the performance of solar cells. The fixed charge density and defect density at the interface of the passivation layer are the key parameters to analyze the passivation effect. Through establishing the MOS model to simulate the capacitance-voltage (C-V) curve of the passivation layer, and using the function to express the simulation curve, this paper establishes the function-based database. The C-V curve obtained from the experiment is compared with the database to find the corresponding function of the experimental data. The passivation parameters N_f and D_it are extracted for analyzing the passivation effect of the passivation layer.

Abstract For 5-year-old Eucalyptus globulus, the optimal liquefaction bark process was explored by analyzing the chemical components of the bark and its liquefaction residue before and after the liquefaction． The results of chemical component determination showed that the contents of cellulose，hemicellulose and lignin of bark were 36.65%, 18.98%, and 45.37% respectively. The contents of benzene-alcohol extractives，hot-water extractives and 1% NaOH extractives were 10.30%, 7.15%, and 23.64% respectively. The content of ash accounted for 7.49%. The liquefaction process showed that the catalytic effect of concentrated sulfuric acid was better than concentrated phosphoric acid. The optimum liquefaction parameters were catalytic of 3% concentrated sulfuric acid，temperature of 160 ℃ and the liquid-solid ratio of 5:1. The liquefaction rate was 82.8% under the above optimal conditions. Compared with raw materials, the cellulose content, hemicellulose content, and lignin content of liquefaction residue reduced by 17.90%, 9.19%, and 15.99%, respectively.

Abstract The research of application, preparation technics, structure and properties for expanded graphite were summarized, and their developing t rends w ere also expected in this paper. The preparation technics of low-temperature expansible graphite, non-sulfur expansible graphite and expanded graphite compound materials synthesized by chemical oxidation, electrochemistry, microwave, detonation or gaseous volatilization were introduced mostly. The investigation actuality and application foreground of expanded graphite materials were summarized and analyzed in their applied fields of airproof, flame retardant, lubricant, environment, catalysis, military affairs and medicine.

Abstract Precious metal catalysts are generally considered to be the best electrocatalysts for slow four-electron transfer mechanism in oxygen reduction and oxygen evolution reactions. However, its large-scale commercialization is limited due to its high cost, scarce resources and lack of stability. Therefore, under the same catalytic performance conditions, low cost and environmentally friendly non-noble metal electrocatalyst will become the focus of future electrocatalyst engineering. Dicyandiamine was used for carbon resource to prepare CoV-based carbon nanotube composites (named CoV-NC) by means of group coordination combined with freeze drying strategy and carbonization treatment. The morphology and structure of the sample was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and N₂ adsorption-desorption curve. In 0.1 M KOH electrolyte, the E_onset potential of CoV-NC catalyst for ORR is 0.931 V, and the limiting current density is higher. The OER voltage is only 1.63 V at the current density of 10 mA·cm^-2, demonstrating that CoV-NC exhibits good catalytic activity of ORR and OER. As for an air-cathode material to assemble primary Zn-air battery, it can discharge continuously for 166 h at a current density of 5 mA·cm^-2, which is much better than commercial Pt/C catalyst.

Abstract Cu₂O/TiO₂ semiconductor heterostructure photocatalytic composite thin films were prepared by the sol-gel method and magnetron sputtering technology. Uniform and transparent TiO₂ thin films were prepared by sol dipping and pulling with butyl titanate as the raw material. P-type Cu₂O thin films were reactive sputtered on the surface of TiO₂ thin films with metal Cu as target source. The catalysts were characterized by SEM, XRD and UV-Vis. The photocatalytic activity of heterojunction composite films under simulated sunlight was investigated by dye degradation experiments, and its mechanism is discussed. The results show that the heterojunction film formed by the composite of TiO₂ and Cu₂O has good photocatalytic activity under simulated sunlight. The heterojunction composite expands the light response range and light response intensity of the catalyst and improves the quantum efficiency. It is a kind of photocatalytic composite film that makes full use of solar energy.

Abstract Hydrogen is one of the most attractive energy sources at present for its excellent properties, such as high energy density, clean and non-pollution energy. Photocatalytic hydrogen evolution is one of the ideal strategies to obtain hydrogen energy. This work aimed to improve the visible-light absorption ability of the structure similar to g-C₃N₄ by anchoring azo groups into the structure. By this, the photocatalytic hydrogen production rate of the resulting product was improved apparently. We use melamine as starting material to prepare Melon, which was further reacted with KOH, PCl₅ and 4, 4-Diaminoazobenzene to get the target Melon/4, 4-Diaminoazobenzene polymer. The condition influencing on the reaction was investigated, such as reaction temperature, the ratio of reactants and concentration of KOH solution. The structure of the as-synthesized polymer was determined IR, XRD, SEM, TGA and EIS. At the same time, its photocatalytic property was investigated.

Abstract Formation energy, crystal structure and electronic structure of C, N doped anatase TiO₂ are calculated based on the density functional theory of plane-wave ultrasoft pseudopotential. Results indicate that, due to doping of the C or N atoms in anatase TiO₂, the lattice distorts obviously. The substitution of C tends to Ti site while N tends to O site. All the substitutions lead to the red shift of the optical absorption and increasing coefficient of light absorption. When N concentrations are 2.08% and 3.13% in N-doped TiO₂, the highest photocatalytic activity is obtained, while it is 2.08% for C-doped one.

Abstract Silicon nitride film containing hydrogen is widely used as antireflection layer and passivation layer in the field of solar cell industrial production. Silicon nitride films containing hydrogen were prepared by industrial plasma enhanced chemical vapor deposition (PECVD) equipment. Fourier Transform Infrared Spectroscopy (FTIR) was used to analyze the composition of the film, to study the influence of reaction gas flow rate and high-frequency power on the composition and properties of the film, and to study the influence of silicon nitride film composition on the passivation effect of the silicon wafer through the minority carrier life of the silicon wafer, so as to clarify the direction of process adjustment in actual industrial production.

Abstract The N-doped graphene/bismuth sulfide (NG/Bi₂S₃) composite was synthesized by hydrothermal method. The structure and properties of the catalyst were characterized by X-ray powder diffraction, Raman spectroscopy, scanning electron microscopy and UV-visible near-infrared diffuse reflectance spectroscopy. The degradation of ammonia-N was studied using 0.050 g NG/Bi₂S₃ as photocatalyst under near-infrared light irradiation. The results show that the degradation ratio of ammonia-N reaches 91.4% in 100.0 mg·L^-1 ammonia-N solution with pH 9.0 under near-infrared light irradiation for 10 h. Under similar conditions，the degradation ratio of ammonia-N is only 65.5% when pure Bi₂S₃ is used as the photocatalyst. Kinetic studies show that the ammonia-N degradation follows the first-order reaction kinetics, and the average value of the apparent rate constant is 0.1240 h^-1. Catalyst stability studies show that the degradation ratio of ammonia nitrogen in 7 runs is still greater than 85.5%, which indicates that the NG/Bi₂S₃ composite catalyst is very stable.

Abstract To improve the cathode electro-catalytic degradation performance of electrochemical advanced oxidation processes (EAOP), Pd metal and CeO_x co-modified Nano-graphite (Pd/CeO_x/Nano-G) composite was synthesized by chemical precipitation and reduction methods, and Pd/CeO_x/Nano-G cathode was prepared by a hot-pressing method. The as-prepared composite and electrode were characterized by X-ray photoelectron spectroscopy, X-ray diffraction and scanning electrons microscopy. Results revealed that the mix-crystal structural CeO_x (Ce₂O₃ and CeO₂) and Pd⁰ metal were formed. The cathode was applied for the electro-catalytic degradation of phenol wastewater. The degradation efficiency of phenol by Pd_1.0/CeO_x5.0/Nano-G cathode reached 99.6% within 120 min degradation, which were higher than that of CeO_x5.0/Nano-G and Nano-G cathodes. Both of the Pd metal and CeO_x could improve the O₂ reduction to H₂O₂ and promote the H₂O₂ dissociation to •OH for phenol oxidation. Additionally, the effects of electro-catalytic reaction parameters on the phenol degradation were investigated. The results indicated that Pd/CeO_x/Nano-G cathode would have promise for further practical application in organic wastewater treatment.

Abstract Ordered mesoporous TiO₂ and their composites have many potential applications in the fields of photocatalysis‚ solar-cells, and so on, due to their special microstructures. The synthesized methods of ordered mesoporous TiO₂ were classified systematically in this paper. The synthesized approaches‚development history, classification and application of mesoporous TiO₂ and their composites are reviewed. Some important progress and research results are also summarized. Based on the present existing problems, the development trend is discussed.

Abstract Carbon-based hollow nanomaterials have recently become one of the hot research topics because of their unique structures, outstanding physicochemical properties and potential applications. The design and synthesis of novel carbon-based hollow nanomaterials have important scientific significance and wide application value. The recent researches on designing of synthesis, structure, function and application of carbon-based hollow nanomaterials are reviewed. The common synthesis strategies of carbon- based hollow nanomaterials are briefly introduced. It is described in detail about the structural designing, material functionalization and main applications of carbon-based hollow nanomaterials. At the end of this review, the current challenges as well as opportunities in the synthesis and application of carbon-based hollow nanomaterials are discussed.