Dilution enthalpies of two α-aminobutyric acid enantiomers, L-α-aminobutyric acid and D-α-aminobutyric acid, in dimethylformide (DMF)+water mixtures of various compositions are determined by isothermal titration microcalorimetry (ITC) at 298.15 K. Homotactic enthalpic pairwise interaction coefficients for each solvent composition are calculated according to the McMillan-Mayer theory of statistical thermodynamics. From the point of view of solute-solute and solute-solvent interactions, competition equilibria among hydrophobic-hydrophobic, hydrophobic-hydrophilic, and hydrophilichydrophilic interactions in ternary solutions are explored. It is found that all values of h_xx are positive across the entire studied composition range of mixed solvents (mass fraction of DMF, w_DMF=0-0.3), gradually reducing with the increasing w_DMF. It is of interest that the h_xx values for the L-enantiomer are universally larger than those of the D-enantiomer (h_LL>h_DD), which indicates that ITC is useful to discriminate homochiral enthalpic pairwise interaction of enantiomers. Our results show that hydrophobic-hydrophobic and hydrophobic-hydrophilic interactions are predominant in pairwise molecular interaction processes in ternary solutions containing α-aminobutyric acid, water, and DMF, and that the configuration of L-L molecular pair is more advantageous for the approach of hydrophobic side-chains (CH₃CH₂－) on α-carbon than a D-D pair, where part of the structured water molecules relax to less structured bulky water due to the overlap and partial breaking of hydrophobic hydration cospheres around nonpolar groups. This confirms that the process is spontaneous and is accompanied with positive enthalpy change and obvious increase in entropy (ΔG<0, ΔH>0, and ΔS=(ΔH-ΔG)/T>0), consequently releasing more heat upon dilution of the solutions and leading to larger values of h_xx.

To understand the experimental observation that the dynamic parameters determined for enthalpy and dielectric relaxation might differ in fragile glass-forming molecular liquids, a fragile molecular liquid, triacetin, was chosen for the study of the two relaxation dynamics. The non-Arrhenius and nonexponential characters were focused, and the kinetic fragility and non-exponential parameter determined from the two relaxation measurements were found to be remarkably similar. Experimental results indicate that the degree of correlation in the molecular motions involved in the two relaxations depends on molecular flexibility. The dependence of the dynamic parameters on molecular structures in the glass forming liquids is discussed.

A reduced chemical kinetic mechanism for the oxidation of three-component fuel comprising iso-octane/n-heptane/ethanol has been developed. The mechanism consists of 50 species and 193 elementary reactions and emphasizes the ignition process. Using path and sensitivity analyses, the path of primary reference fuel (PRF) oxidation and major elementary reactions at high and low temperatures are given. The validated results show that the present mechanism gives od agreement with experimental data for ignition delay time predictions. Because of the few species and reactions presenting in the chemical kinetic model, the mechanism is applicable to multidimensional computational fluid dynamic (CFD) simulation of the co-combustion of gasoline with ethanol.

Molecular dynamics (MD) simulations usually analyze the structure of a phase by radial distribution function (RDF), the Honeycutt-Anderson (HA) bond pair analysis, and the cluster-type index method (CTIM). In this paper, we improve CTIM to allow the characterization of more kinds of crystal structure besides bccfcchcp on-crystal based on the theory of CTIM. The crystal structures of Zn-Mg alloys have been characterized and the phase distribution of the Zn-Mg diffusion system has been analyzed by CTIM. The results show that the CTIM integers can reveal differences between the Mg₂₁Zn₂₅, MgZn₂, and Mg₂Zn₁₁ structures, and similarities between the Mg₄Zn₇ and MgZn₂ structures. Using a two-step simulation on the Zn-Mg diffusion system, fcc and hcp crystals occur at both extremes of the system and there are many non-crystal phases in the middle of the system. In addition, our results show that the interface structure of fcc and hcp crystals on the Zn side is mainly Zn12-C.

The structures, surface-enhanced Raman scattering (SERS), and pre-resonance Raman spectra (SERRS) of Aflatoxin B₁ (AFB₁)-Ag_n (n=2, 4, 6) complexes were calculated using density functional theory (DFT) with the B3LYP/6-311G(d, p) (C, H, O)/LanL2DZ (Ag) basis set. The results show that the SERS enhancement factors were about 10²-10³ for the AFB₁-Ag_n (n=2, 4, 6) complexes, respectively. This is due to the C＝O stretch of the pyran ring and the larger static polarizability of the three complexes. The SERS spectra were consistent with the experimental results. The SERRS spectra of the three complexes were obtained by excitation at 407.5, 446.2, and 411.2 nm, which were close to the electronic excitation energy of absorption spectra as determined by time-dependent density functional theory (TDDFT). The SERRS enhancement factors caused by the charge-transfer excitation resonance were about 10⁴, which corresponds to the Ag―O stretching.

We established periodical structures for Ni-Mg-Al hydrotalcites (HT) by isomorphous substitution of Mg²⁺ with Ni²⁺. We discussed the supramolecular structure, electronic property, and stability of the systems according to computational results based on density functional theory. As Ni²⁺ content of increased, the average distance between metal cations decreased while the interlayer spacing gradually increased, in agreement with the experimental data. At the same time, electrons gradually transferred from layer to interlayer anions. As a result, the electrostatic interaction, whole supramolecular interaction, and absolute binding energy value of the system increased, improving system stability. Meanwhile, the average M－O bond length decreased, and the distorted O－M－O angles were weakened to some degree. All of these changes are beneficial to the formation of a stable system, so we conclude that Ni-Al-HT is more stable than Mg-Al-HT.

A Nano-TiO₂/poly(citric acid titanium complex-polyethylene glycol)/LiI/I₂ crosslinked hybrid polymer electrolyte membrane has been prepared via in-situ polymerization and compositing. Specifically, the method used the synthesized crosslinked network of poly(citric acid titanium complex-polyethylene glycol) containing the Ti(VI) hybrid center as a substrate, the hydrolyzed Nano-TiO₂ as fillers and LiI/I₂ as conductive ionics. The formation mechanism of the crosslinked hybrid polymer matrix is discussed. A structural model was established with a local density approximation (LDA) method. The influence of Ti(iOPr)₄ content on the structure and electrochemical performance of the electrolyte membrane were investigated with Raman spectra, Fourier transform infrared spectra (FTIR), transmission electron microscopy (TEM), and an energy dispersive X-ray analysis (EDXA) technique. It was found that when the Ti(iOPr)₄ content was higher than 12% (w), the combined action of Nano-TiO₂ particles and the Ti(VI) hybrid center improved not only the room-temperature ionic conductivity (σ), but also the interfacial stability. At 48% (w) Ti(iOPr)₄ content, the value of σ reached a maximum of 9.72×10^-5 S·cm^-1 and the interface resistance became stable after 6 d.

Cathodic materials La_1.6Sr_0.4Ni_1-xCu_xO₄ (x=0.2, 0.4, 0.6, 0.8), for an intermediate temperature solid oxide fuel cell (IT-SOFC), were prepared by a glycine-nitrate process and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). Results showed that no reaction occurred between the La_1.6Sr_0.4Ni_1-xCu_xO₄ electrode and the Ce_0.9Gd_0.1O_1.95 (C ) electrolyte at 1000 °C, and that the electrode formed od contact with the electrolyte after sintering at 1000 °C for 4 h. Electrochemical AC impedance spectroscopy measurements were used to study cathodic performance. The La_1.6Sr_0.4Ni_0.4Cu_0.6O₄ cathode gave the lowest polarization resistance (R_p) of 0.35 Ω·cm² at 750 ° C in air. Electrode properties of La_1.6Sr_0.4Ni_1-xCu_xO₄ were studied under various temperatures and oxygen partial pressures. The two main oxygen reduction processes at the cathode are the oxygen ion transfer from the triple phase boundary to C electrolyte, and the charge transfer process. Charge transfer is the major rate limiting step for La_1.6Sr_0.4Ni_1-xCu_xO₄ cathode. The La_1.6Sr_0.4Ni_0.4Cu_0.6O₄ cathode exhibited the lowest overpotential, about 45 mV for a current density of 45 mA·cm^-2 at 700 °C in air. This preliminary work showed that the present La_1.6Sr_0.4Ni_1-xCu_xO₄ materials may be potential cathodes for use in IT-SOFCs.

Hollow CoPt nanospheres were synthesized by chemical reduction and galvanic displacement reactions. The catalyst showed od electrocatalytic activity for methanol oxidation. The results of transmission electron microscopy (TEM), energy dispersive spectromenter (EDS), and electrochemical cyclic voltammograms indicated that, in the process of electrochemical experiments carried in 0.1 mol·L^-1 H₂SO₄ and 0.1 mol·L^-1CH₃OH, hollow CoPt nanospheres were dealloying, which induced the dissolution of elemental Co from the surface of the catalyst. After the dealloying process, more Pt active sites were exposed on the surface of the catalyst and the catalyst showed better catalytic activity, as well as enhanced structural stability. The electrooxidation of methanol on the hollow CoPt nanospheres was studied on the molecular level using in situ electrochemical Fourier transform infrared (FTIR) spectroscopy. The toxic intermediate CO observed on the CoPt nanorods displayed abnormal infrared effects (AIREs). The FTIR results were similar to those obtained in an earlier experiment on the hollow CoPt nanospheres using CO as a probe molecule. All the results suggested that the dealloying method would be a useful technique for regulating the composition and performance of the catalyst. In situ electrochemical FTIR was highlighted as a potential method for studying the oxidation processes of organic molecules. It is envisaged that these methods will be widely used in the field of fuel cell research.

A monotungsten carbide (WC)/bitungsten carbide (W₂C) nanocomposite having a core-shell structure was prepared through a combination of surface coating and in situ reduction-carbonization, using ammonia meta-tungsten as tungsten source and iron oxide hydroxide as a hard support. The crystal phase, morphology, microstructure, and chemical components of the samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray energy dispersion spectroscopy (EDS). The results show that after calcination, the morphology, the crystal phases of the support, and the coating layer around the support are changed. After acid dissolution, reduction, and carbonization, the crystal phase of the final product is composed of WC and W₂C; the microstructure of the sample particle is a core-shell structure in which WC forms the core and W₂C forms the shell. Based on the characterization results, the formation mechanism of the core-shell structure is discussed. The electrocatalytic activities of the samples for methanol electrooxidation were investigated by cyclic voltammetry with a three-electrode system in acidic, neutral, alkaline aqueous solutions. The results show that the electrocatalytic activity of the sample for methanol oxidation is higher than that of tungsten carbide particles and hollow microsphere tungsten carbide. These indicate that the electrocatalytic activity of tungsten carbide can be improved through the formation of core-shell structure, and it is one of the efficient ways to improve the electrocatalytic activity of tungsten carbide.

Mg and Ti ions co-doped (Li_0.98Mg_0.01)(Fe_0.98Ti_0.01)PO₄/C cathode material for lithium-ion batteries was prepared by a solid-state method under N₂ atmosphere. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and galvanostatic charge-discharge test. Results indicated that Mg and Ti ions co-doping remarkably improved the electrochemical performance of LiFePO₄, including rate capacity, temperature behavior, and cycling stability. Discharge capacities of 154.7 and 146.9 mAh·g^-1 were obtained at the rates of 0.2C and 1C for half-cell tests, respectively. For 60 Ah full-cell tests, 100% of 1C capacity was maintained even at 3C rate, 89.7% and 63.1% of initial capacity at room temperature were retained at 0 and -20 °C, respectively. 89% capacity retention remained after 2000 cycles at room temperature, presenting excellent cycle stability. This investigation suggests that the present co-doping material and the resulting battery possess large discharge capacity and excellent cycling performance, making it applicable in electric vehicle (EV)/hybrid electric vehicle (HEV) and energy storage systems on a large scale.

1,2-Dimethoxy-4-nitro-benzene (DMNB1) and 1,4-dimethoxy-2-nitro-benzene (DMNB2) were selected as new redox shuttle additives for overcharge protection in lithium-ion batteries. The base electrolyte is 1 mol·L^-1 LiPF₆/(ethylene carbonate (EC)+diethyl carbonate (DEC)+ethyl-methyl carbonate (EMC) (1:1:1, by volume)). Cyclic voltammetry (CV), charge-discharge cycle performance, overcharge tests, electrochemical impedance spectra (EIS), and scanning electron microscopy (SEM) were used to investigate the electrochemical performances of DMNB1 and DMNB2. The overcharge protection of DMNB1 and DMNB2 on lithium-ion batteries and the compatibility of both additives with the LiNi_1/3CoMn_1/3O₂ electrode have been studied. The results show that the working potentials of the both additives are above 4.3 V (vs Li/Li⁺), and thus are suitable for overcharge protection in lithium-ion batteries. Lithium-ion batteries with DMNB1 and DMNB2 have an improved overcharging tolerance. DMNB1 shows better overcharge protective performance, in the 100% overcharge and 5 V cutoff voltage tests, than DMNB2. After 100 cycles at 0.2C rate, the capacity retention rates of the LiNi_1/3Co_1/3Mn_1/3O₂/Li cells with the base electrolyte and the electrolyte with DMNB1 and DMNB2 are 98.4%, 95.9%, and 68.1%, respectively. The electrochemical properties and the location of the nitro-group on the benzene of the overcharge protection additives are closely linked.

The pitting corrosion of AA6063 aluminum alloy in 3% (w) NaCl solution was investigated by electrochemical noise (ECN), electrochemical impedance spectroscopy (EIS), and polarization curves. Inhibition of nucleation and propagation of metastable pits by inhibitors, such as CeCl₃, Na₂CrO₄, and 8-hydroxyquinoline (8-HQ), was evaluated based on ECN data statistics. It was found that the local pH could be over 8.4 near the cathode phase (Al-Si-Fe) due to dissolution of Al matrix, leading to preferential deposition of Ce(OH)₃ on the surface of the cathode phase, thereby inhibiting the cathodic process of pitting corrosion. The average electric charge (q) of metastable pits decreased with increasing the corrosion inhibitor concentration, but the average lifespan of noise transients remained almost constant, indicating that Ce³⁺ ions did not accelerate the rehabilitation of metastable pits directly, but reduced the dissolution rate of Al inside active pits. However, CrO₄^2- ions not only accelerated the rehabilitation of metastable pits, but also reduced the nucleation rate of the AA6063 aluminum alloy. In contrast, 8-HQ acted as an effective corrosion inhibitor for AA6063 aluminum alloy through formation of insoluble chelate films with Al³⁺ ions and Mg²⁺ ions, but failed to enhance the pitting corrosion resistance of the aluminum alloy.

An organotemplate-free hydrothermal route was investigated for synthesizing isomorphously Co-substituted mordenite molecular sieve using only the inorganic raw materials such as sodium silicate, aluminum sulfate, cobalt nitrate, and sodium hydroxide. Textural properties and Co ion states for the obtained solid products were characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), inductively coupled plasma (ICP), nitrogen adsorption, ultraviolet-visible (UV-Vis) spectra, and thermogravimetric (TG) analysis. The results showed that Co ions were incorporated into the framework structure of the mordenite without the presence of extra-framework Co species. Typical synthesis conditions were n(Co)/n(SiO₂)=0.01-0.04, n(SiO₂)/n(Al₂O₃)=20-50, n(H₂O)/n(SiO₂)=40, n(Na₂O)/ n(SiO₂) =0.4, crystallization temperature 170 ° C, and crystallization time 3-7 d. The structure-directing function of Na+ ions in the absence of an organic template was discussed. Products obtained by the present allinorganic systems possess open micropores and do not require traditional high-temperature calcination. Thus, we demonstrate a low cost, low energy consumption, and environmentally benign synthesis of Co-mordenite.

Shaped binderless ZSM-5 zeolites were prepared via a rapid dry-gel conversion technique from aluminosilicate extrudate. Silica gel and boehmite were well mixed and extruded into cylindrical shaped extrudates with diameter of 2 mm with the aid of silica sol, ZSM-5 zeolite seed gel, and/or tetrapropylammonium hydroxide (TPAOH) solution. The total molar ratio of TPAOH to SiO₂ was fixed at 0.025. With same amounts of structure directing agent (TPAOH), the addition of seed gels accelerated the crystallization of the zeolite. The seed gel directing agent composition was 0.35TPAOH:1SiO₂:20H₂O: 4C₂H₅OH. The seed gel not only provided crystal nuclei for rapid crystallization but also controlled the size of the ZSM-5 crystals. Especially, the morphology of these extrudates was well maintained in the crystallization process. The crystallization processes of zeolite were characterized by X-ray diffraction (XRD), thermogravimetric (TG) analysis, and Fourier transform infrared (FTIR) spectroscopy. The results showed that the growth of the zeolite was accompanied by the occupation of the zeolite channels by TPAOH. When the TPAOH/SiO₂ molar ratio was 0.025, the sample achieved 100% relative crystallinity after 3 h crystallization. The morphology and textural properties were characterized by scanning electron microscopy (SEM) and nitrogen sorption isotherms. The obtained shaped zeolites comprised nanosized crystals (200 nm) and exhibited a hierarchical structure with high mesopore volume (0.28 cm³·g^-1). The temperature- programmed desorption of ammonia (NH₃-TPD) was used to assess the acidity of these shaped zeolites. The results showed that this shaped zeolite possessed an acidity similar to that of a commercial H-ZSM-5 catalyst.

Catalytic conversion of methanol to propylene (MTP) by HZSM-5 zeolite is of great importance in industrial applications. In this paper, a series of HZSM-5 zeolites with different crystal sizes were synthesized by adjusting the initial gel composition, crystallization temperature, and crystallization time. The crystal structure, size, morphology, pore structure, and acidity of HZSM-5 were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption, and temperature-programmed desorption of ammonia (NH₃-TPD). The catalytic activity and stability of HZSM-5 with different crystal sizes for MTP were evaluated on a continuous flowing fixed-bed reactor. Coke deposited on HZSM-5 was analyzed by thermogravimetric (TG) analyzer. Results indicated that with smaller crystal size, HZSM-5 zeolite had larger surface area and pore volume, higher density of pore openings, and shorter path length of micropore channels that prevent side reactions. For MTP reaction, smaller crystal sizes of HZSM-5 showed a higher resistance and better tolerance to coke, and longer catalytic lifetime. The lowering of both the total and strong acidity on HZSM-5 with smaller crystal size favored a higher selectivity of target product, propylene.

Perovskite-type La_0.8Sr_0.2Fe_1-xSc_xO_3-δ (LSFS, x=0, 0.3, 0.4, 0.5, 0.6, 0.8, 1) catalysts were prepared by glycine-nitrate solution combustion. The catalysts were characterized by X-ray powder diffraction (XRD), H₂-temperature-programmed reduction (H₂-TPR), scanning electron microscopy (SEM), and specific surface area measurements. The catalytic performance of LSFS for methane combustion was investigated in a micro fixed-bed reactor. The results showed that all the LSFS catalysts have a single perovskite structure after calcining in air at 900 °C for 5 h. By doping Sc into La_0.8Sr_0.2FeO_3-δ, the sintering agglomeration between the LSFS particles is weakened, and therefore the specific surface area is increased. At Sc dopings of 0.4-0.6, the resultant LSFS gives od catalytic activity for methane combustion, with a light-off temperature (T₁₀) of 406 °C and a total conversion temperature (T₉₀) of 563 °C at a Sc doping of 0.5. Compared with La_0.8Sr_0.2FeO_3-δ and La_0.8Sr_0.2ScO_3-δ the T₁₀ is decreased by 14 and 87 °C, and T₉₀ is decreased by 59 and 95 °C, respectively.

A series of mesoporous alumina supported nickel oxide, cobalt oxide, and bimetallic nickelcobalt oxide catalysts were synthesized by a one-pot method, using nonionic triblock copolymer as a template and aluminum isopropoxide as the source of aluminum. For comparison, an additional supported Ni-Co oxide catalyst was prepared by impregnation, using mesoporous alumina as the support. The catalysts were tested for the oxidative dehydrogenation of propane, and their structure and properties were characterized by N₂ adsorption-desorption, high-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), temperature-programmed H₂ reduction (H₂-TPR), and laser Raman spectroscopy (LRS). All samples synthesized by the one-pot method had large surface area, highly ordered mesoporous structure, and highly dispersed supported oxide species. However, in the sample prepared by impregnation, the mesostructure of the carrier was destroyed with the formation of Co₃O₄ phase. Among the catalysts studied, the mesoporous alumina supported Ni-Co oxide catalyst from one-pot synthesis showed the best catalytic performance for propane oxidation to propylene. On this catalyst a 10.3% propylene yield was obtained at 450 ° C, C₃H₈:O₂:N₂ molar ratio of 1:1:4, and gas hourly space velocity (GHSV) of 10000 mL·h^-1·g^-1. This result was much higher than the yield of 2.4% obtained from the catalyst prepared by impregnation. Combining the results of characterization and catalytic reaction, the relationship between structure and performance of the catalysts was discussed. The large difference observed in catalytic performance between catalysts prepared by one-pot and impregnation methods was attributed to their different structures, including textural structure, and dispersion of the supported metal oxide species.

N-alkyl anilines were obtained from nitroaromatics by a one-pot method using assembled Pt₃Sn/Al₂O₃ catalyst for heterogeneous in situ hydrogenation in a continuous-flow fixed-bed reactor. At the optimum reaction conditions (503 K, liquid hourly space velocity (LHSV) of 7.5 h^-1, 5% (volume fraction) water, 1% (mass fraction) Pt₃Sn/Al₂O₃ catalyst), nitrobenzene conversion was 100%, with a total N-ethyl and N,N-diethyl aniline yield of 98.2%. Moreover, the Pt₃Sn/Al₂O₃ catalyst had a great conjoint effect for all in situ hydrogenation reactions for N-alkylation. High yields of N-alkylation products were obtained in aliphatic alcohol/water systems for 14 selected nitroaromatics.

Fe-doped SO₄^2-/SnO₂ (STF) solid acid catalysts with different amounts of iron were prepared via co-condensation, followed by sulfation and calcination. These materials were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD), N₂ adsorption-desorption analysis (BET), thermogravimetric (TG) analysis, and scanning electron microscopy (SEM). The Fe-doped catalysts exhibited more activity than undoped catalysts in acetalization reactions of 4-tert-butylcyclohexanone and diols. The catalytic acetalization of several ketones and 1,2-diols with the SO₄^2-/SnO₂-Fe₂O₃ catalysts (with the Fe/Sn molar ratio of 0.5) were studied. The influence of the reaction time and the amount of the catalysts on the acetalization were also investigated. In addition, the high performance of this Fe-modified catalyst was demonstrated in the Baeyer-Villiger oxidation of cyclic ketones. The catalyst can be recycled several times without any significant loss in catalytic activity.

Anionic polystyrene (PSt) latex particles were synthesized by emulsion polymerization of methacrylic acid and styrene (St). The anionic PSt particles were surface treated with vinyl trimethoxysilane in a mixture of ethanol and water. PSt/TiO₂ composite particles doped with Ag₂O were then prepared through hydrolysis of tetrabutyl titanate and AgNO₃ using the surface treated PSt particles as templates. Hollow Ag-TiO₂ particles were successfully prepared by treating the PSt/TiO₂ composite microspheres at 180 °C, after which they were dried and calcined at 500 °C. The morphology of the PSt/TiO₂ particles and crystal structure of the Ag-TiO₂ hollow particles were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Photocatalytic activity of the Ag-TiO₂ hollow particles for Rhodamine B (RhB) degradation was tested under ultraviolet (UV, 365 nm) and UV-visible (370-760 nm) light. Under UV light, RhB degradation was increased by about 11% when Ag-TiO₂ particles with molar ratio n_Ag/n_Ti of 0.1% were used compared with pure TiO₂ hollow particles. Under UV-visible light, RhB degradation was increased by about 30% for Ag-TiO₂ composite particles with n_Ag/n_Ti of 1.0% and 2.0%.

Polycrystalline TiO₂ thin films were prepared by direct current facing-target magnetron sputtering at different sputtering pressures and Ar/O₂ flow ratios. The average thickness of all prepared films was 200 nm, measured by surface roughness tester. With increase in sputtering pressure (p_tot), the prepared films changed from mixtures of anatase and rutile phases to pure anatase. The influences of different sputtering pressures and Ar/O₂ flow ratios on surface morphology of prepared films were investigated by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The film surface was found to become rougher with increasing pressure and Ar/O₂ flow ratios. Photocatalytic activities of the prepared TiO₂ thin films were investigated by decomposition of iso-propanol (IPA) with initial concentration of 100×10^-6 (volume fraction) under UV irradiation. The IPA was oxidized to acetone and further to carbon dioxide. TiO₂ thin film deposited at 2.0 Pa with an Ar/O₂ flow ratio of 1:1 showed the highest photocatalytic activity and maintained a high stability constant during the reaction.

Bi₂O₃/TiO₂ nanotube arrays (NTs) were prepared by depositing Bi₂O₃ nanoparticles (NPs) onto the tube wall of self-organized TiO₂ NTs using an impregnation-decomposition method. Chemical composition of the resulting Bi₂O₃/TiO₂ NTs was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-visible (UV-Vis) diffuse reflectance spectroscopy. Photocatalytic activity was evaluated by degradation of aqueous methyl orange (MO) solution under visible-light irradiation (λ>400 nm). The Bi₂O₃ nanoparticles were found to be uniformly deposited into the nanotubes. Bi₂O₃/TiO₂ NTs exhibited much higher visible-light activity than pure Bi₂O₃ films and N-TiO₂ NTs, which was attributed to synergistic effects of the strong visible-light absorption of Bi₂O₃/TiO₂ NTs and the heterojunction formed between Bi₂O₃ and TiO₂.

Manganese oxides supported on multi-walled carbon nanotubes (MnO_x/MWCNTs) catalysts were prepared by pore volume impregnation using MWCNTs as the catalyst support which was pretreated by concentrated nitric acid and oxygen dielectric barrier discharge plasma. The catalysts were characterized by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction/desorption (TPR/ TPD), and Fourier transform infrared (FTIR) spectroscopy. The effect of SO₂ on the activity of the catalysts for low-temperature selective catalytic reduction (SCR) of NOx by ammonia and the SO₂ poisoning mechanism were investigated. The results showed that SO₂ had an obvious poisoning effect on the SCR activity of MnO_x/MWCNTs at low temperature. The activity decreased more rapidly as reaction temperature and SO₂ concentration increased. The observed deactivation was attributed to the sulfation of the active center atoms. Formation of ammonium sulfate on the catalyst surface and the inhibiting effect of SO₂ on NO adsorption also resulted in the deactivation of the catalysts to some extent.

α-Fe₂O₃and SiO₂were prepared from ferric nitrate and TEOS by sol-gel method in combination with using templates. The synthetic samples were characterized by powder X-ray diffraction (XRD) and N₂adsorption/desorption methods. We determined the surface acid-base properties of α-Fe₂O₃/SiO₂nano-mixed system by potentiometric titration technique, and studied the adsorption behaviors of heavy metal ions on the solid surface of α-Fe₂O₃/SiO₂nano-mixed system at different pH values. According to the above experimental data, we calculated the surface acid-base reaction equilibrium constants of the nano-mixed system using WinSGW software to be ≡XOH ⇔ ≡XO^-+ H⁺(lg K = -8.19±0.15). The calculated result reveals that the single deprotonation surface of α-Fe₂O₃/SiO₂nano-mixed system is obviously different from the surfaces of α-Fe₂O₃/SiO₂/γ-Al₂O₃, α-Fe₂O₃/γ-Al₂O₃ and SiO₂/γ-Al₂O₃nano-mixed system with surface protonation as well as deprotonation at the same time. Based on the above result, the surface complexation constants of Cu²⁺, Pb²⁺, Zn²⁺on the surface of α-Fe₂O₃/SiO₂mixed systems were simulated respectively as follows:
≡XOH + M²⁺ ⇔ ≡XOM⁺+ H⁺ [lg K =-3.1, -3.6, -3.8 (M = Cu, Pb, Zn)].

Sulfonium ion glucosidase inhibitors such as kotalanol (SK) and de-O-sulfonated kotalanol (DSK) are potential drug candidates for the treatment of type II diabetes, with no serious toxicity or side effects. Experimental binding assays against glucosidase show that the activity of DSK is slightly higher than that of SK, while the activity of the nitrogen analogue of de-O-sulfonated kotalanol (DSN) is ~1500-fold higher than that of the nitrogen analog of kotalanol (SN). Here, the binding mechanisms of four representative inhibitors of glucoamylase, SK, DSK, and their two nitrogen analogues, were explored in an integrated modeling study combining molecular dynamics (MD) simulations, binding free energy calculations, and binding free energy decomposition analysis. Our simulations highlight the significant impact of the combination of nitrogen substitution and sulfate anion group. Nitrogen substitution in the five-membered ring leads to the overturning of the polyhydroxylated chain, originating from the shorter bond length of N―C compared with S ― C, while the sulfate anion group restrains the freedom of the polyhydroxylated chain. These cumulative effects are able to significantly change the binding conformation of the inhibitor and substantially impair interactions between the inhibitor and glucosidase. The structural insights obtained in this study are expected to be valuable for increased understanding of the binding mechanism of sulfonium ion glucosidase inhibitors and future design of more potent glucosidase inhibitors.

Two kinds of Ag/CNTs (carbon nanotubes) nanocomposite materials were successfully prepared by silver mirror reaction and hydrothermal methods. Their physical phase, composition, morphology, and structure were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscope-energy dispersive spectrometry (SEM-EDS). Catalytic effects of the Ag/CNTs nanocomposite on the thermal decomposition of cyclotrimethylene trinitramine (RDX) were investigated by differential scanning calorimetry (DSC). Our results indicated that the irregularly globose nano-Ag particles attached to the surface of the nano CNTs evenly. The nanocomposite product prepared hydrothermally had the highest loading of nano-Ag particles and largest Ag particle size. Both Ag/CNTs nanocomposites influenced the thermal decomposition of RDX, changing the primary decomposition of the liquid phase to a secondary gas phase reaction and resulting in obvious change in the shape of the main decomposition peak. The catalytic effect of Ag/CNTs nanocomposite on the thermal decomposition of RDX was mainly exhibited at lower decomposition temperature.

Branched palladium nanostructures were synthesized under microwave irradiation using polyvinylpyrrolidone (PVP) as stabilizer and benzyl glycol as the reducing agent of H₂PdCl₄. Morphology and structure were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), and showed that the branched Pd nanostructures were self-assemblies of hundreds of small spherical nanoparticles. Furthermore, catalytic properties of the branched Pd nanostructures were investigated for the hydrogenation of nitrobenzene, which indicated that the catalytic activity of the branched Pd nanostructures for this reaction is higher than that of a conventional Pd/C catalyst.

Hierarchical porous hematite (HPH) network structures were successfully constructed using an improved polymerization induced colloid aggregation process with Fe(NO₃)₃·9H₂O as the raw material. The polymerization between urea and formaldehyde into urea-formaldehyde (UF) resin is the key factor for this construction. The UF resins appear to be advantageous in two respects: the UF oli mer hybrids with ferric hydroxide (Fe-UF) and UF polymer formed microcapsules (UFM) acted as templates to induce the aggregation of Fe-UF hybrids into mesoporous spheres. The further crosslink reactions among the hybrid spheres generate the network structure. After calcination, the decomposition of the UF resin and the UFM produces nanopores in the nanorod subunits and macropores in the network structure, respectively. The photodegradation activity of the unique structured HPH is four times that of the commercial hematite nanoparticles with rhodamine B (RhB) as pollutant.

Fe₃O₄-TiO₂ nanoparticles with different doped amounts of Fe₃O₄ were prepared by three sol-gel methods at low temperature. They were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, fluorescence spectroscopy (FS), and magnetic performance. The nanoparticles which had uniform coating, od dispersion, excellent magnetism, and high photocatalytic activity were screened. The survival rates of hepatoma carcinoma cells (HepG2) were measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) cell proliferation assay, and the photo-killing effect of screened Fe₃O₄-TiO₂ nanoparticles on HepG2 cells was investigated in different external magnetic fields. The results indicated that the core-shell structure 5% (mass fraction) Fe₃O₄-TiO₂ nanoparticles prepared by the third method displayed od dispersion in suspension, high photocatalytic activity, and excellent magnetic responsivity. The average particle size of the 5%Fe₃O₄-TiO₂ particles was 50 nm. Meanwhile, the photoresponsive range of TiO₂ was extended to 444 nm. In the external magnetic fields, the Fe₃O₄-TiO₂ nanoparticles excited either by ultraviolet or visible light showed no obvious difference on killing effect, while in both cases had a higher killing effect than that of nano-TiO₂. Furthermore, the killing effect was enhanced with the increased magnetic field strength in the range of 0-1.0 T.