Graphene-like molybdenum disulfide (MoS₂), which is composed of a monolayer or few layers of MoS₂, is a new two-dimensional (2D) layered material that has attracted considerable attention recently because of its unique structure and optical and electronic properties. Here we first review the methods used to synthesize graphene-like MoS₂. “Top-down” methods include micromechanical exfoliation, lithium-based intercalation and liquid exfoliation, while the“bottom-up”approaches covered are thermal decomposition and hydrothermal synthesis. We then discuss several methods used to characterize the 2D layered structures of MoS₂, such as atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. We describe the UV-Vis absorption and photoluminescent properties of graphene-like MoS₂ and their related mechanisms. Finally, we summarize the application of graphene-like MoS₂ in various optoelectronic devices such as secondary batteries, field-effect transistors, sensors, organic light-emitting diodes, and memory. The application principles and research progress are discussed, followed by a summary and outlook for the research of this emerging 2D layered nanomaterial.

The phase behaviors of 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim] [PF₆]) + water+methanol, [bmim][PF₆]+water+ethanol, [bmim][PF₆]+water+2-propanol, and [bmim][PF₆]+water+1- propanol ternary systems were determined at 298.15 K and ambient pressure. It was demonstrated that when the mole fractions of the alcohols in the water+alcohol solutions were 0.55-1.00, 0.40-0.75, and 0.35-0.50 for methanol, ethanol, and 2-propanol, respectively, the [bmim][PF₆] was totally dissolved in the aqueous alcohol solutions due to a strong co-solvent effect. However, water+1-propanol did not exhibit this kind of behavior. Both the size and structure of the alcohols significantly affected the phase behaviors of the ternary systems.

Bimolecular rate constants for the gas-phase reactions of C₂(X¹Σ_g⁺) with unsaturated hydrocarbons C₂H₄ and C₂H₂ were measured over the temperature range 293-573 K by pulsed laser photolysis/laserinduced fluorescence (PLP-LIF). The rate constants, in the unit of cm³·molecule^-1·s^-1, can be fitted by the normal Arrhenius expressions: k(C₂H₄)=(1.16±0.10)×10^-10exp[(290.68±9.72)/T], and k(C₂H₂)=(1.36±0.02)×10^-10exp[(263.85 ± 7.60)/T], where all error estimates are ± 2σ and represent the precision of the fit. The observed bimolecular rate constants along with the negative temperature dependences of k(T) allow us to conclude that the reactions of C₂(X¹Σ_g⁺) with these unsaturated hydrocarbons in the temperature range 293- 573 K proceed via an addition mechanism.

The pyrolysis of n-decane and dimethylbenzene under supercritical pressure was studied using a continuous flow reactor. Samples were heated to a temperature of 650, 700, or 750 ℃ under a pressure of 4 MPa without oxygen. n-Decane pyrolyzed more easily than dimethylbenzene. We analyzed gaseous products by online gas chromatography, and liquid products by gas chromatography-mass spectrometry, allowing us to calculate the cracking gas yield and cracking conversion of these systems. A quantum chemistry computation was used to evaluate the binding energies of C－C and C－H bonds in n-decane and dimethylbenzene. Both experimental and theoretical results were also used to analyze the cracking reactivity of these species. Analysis of the components in the products indicated that the main products of n-decane were C₁-C₃ hydrocarbons and hydrogen, whereas ethylbenzene, toluene and other aromatic compounds were the main products of dimethylbezene after pyrolysis. Binding energy calculations showed that both C－C and C－H bonds in n-decane possessed lower binding energies than those in dimethylbezene, and a C－C bond was the weakest. In dimethylbenzene, a C－H bond in the methyl groups was the weakest, and its binding energy was much smaller than those of the C－C and CH bonds in the benzene ring. Therefore, the main reactions in the cracking process of n-decane are breakage of a C－C bond and dehydrogenation. However, the cracking process in dimethylbenzene mainly involves the fracture and dehydrogenation of methyl groups. The theoretical calculations reasonably explained the experimental phenomena.

Femtosecond two-dimensional infrared (2D IR) spectroscopy, steady-state infrared spectroscopy, and computational methods are used to examine the ultrafast structural dynamics of a β-peptide model compound, N-ethylpropionamide (NEPA). NEPA has amide-I vibrational characteristics similar to that in an α-peptide, which shows sensitivity to molecular structure and chemical environment. The 2D IR spectral dynamics reveal a spectral diffusion time of ~1 ps, which is believed to be consistent with the time scale of the structural dynamics of the amide-water hydrogen bond.

A novel transition metal iron(II) sulfate containing hydrazine (N₂H₄) ligand: [Fe(N₂H₅)₂(SO₄)₂]_n (1), is prepared by a hydrothermal method. Single-crystal X-ray diffraction reveals that 1 consists of onedimensional (1D) sulfate-bridged homometallic chains with protonated hydrazine molecules as terminal ligands. Hydrogen bonds between protonated hydrazine and sulfate ions connect the chains into a threedimensional (3D) extended framework. Magnetic measurements indicate that 1 exhibits the antiferromagnetic ordering behavior at low temperature.

The relationship between the molecular configuration and bulk behavior of partially hydrolyzed hydrophobically modified polyacrylamide (HMHPAM) in aqueous solution was studied via dissipative particle dynamics (DPD) simulation. The influence of the polymer concentration, polymerization process, degree of hydrolysis, and the hydrophobic modified group of HMHPAM on the polymer solution, especially the extent of expansion of the polymer and the viscosity of the polymer solution, were investigated quantitatively by calculating the root-mean-square (RMS) end-to-end distance of the polymer and the water molecule diffusivity. The influencing mechanisms of the type and the arrangement of the repeating unit of the polymer chains on the HMHPAM solution properties were studied to direct the practical synthesis, modification, and application of the polymer.

Heterogeneous nucleation often occurs in the atmosphere, but its microscopic mechanism is mostly unknown. In our work, molecular dynamics simulations were performed to explore the dynamic characteristics of the heterogeneous nucleation of supersaturated ar n vapor onto a spherical solid nanoparticle. We discuss the effect of the cooling rate on the evolution of the system temperature, the cluster distribution, the cluster size, and the nucleation rate during the nucleation process. Our results show that the pre-existing nucleus plays an important role in the cluster formation stage. Furthermore, in the system with a pre-existing heterogeneous nucleus, a critical cooling rate (1.8×10^-9J·s^-1) exists at which homogeneous nucleation emerges and coexists with heterogeneous nucleation but heterogeneous nucleation still dominates the entire nucleation process.

The selective oxidation of styrene on oxygen-covered Ag(110) and Ag(111) surfaces is studied by density functional theory (DFT) calculations with the periodic slab model. On the Ag(110) surface, a pre-adsorbed oxygen atom prefers the 3-fold hollow site (3h) with an adsorption energy of -3.59 eV. On the Ag(111) surface, the most stable adsorption site for a pre-adsorbed oxygen atom is the fcc site, and the adsorption energy is -3.69 eV. The reaction process of the selective oxidation of styrene includes two steps: the formation of surface intermediates (branched oxametallacycle and linear oxametallacycle) and the subsequent formation of different products. The calculated results show that the formation of styrene oxide via the linear oxametallacycle (i.e., the pre-adsorbed atomic oxygen bound to the methylene group in styrene) is the favorable reaction mechanism on both Ag(110) and Ag(111) surfaces. The reaction barriers for the different reaction steps of styrene epoxidation on the Ag(110) surface are generally higher than those on the Ag(111) surface. Moreover, the micro-kinetic simulation results indicate that the relative selectivity towards the formation of styrene oxide on the Ag(111) surface is much higher than that on the Ag(110) surface (0.38 vs 0.003) because the energy barrier for the styrene epoxidation is smaller than that for the formation of phenyl acetaldehyde and its combustion intermediate on Ag(111) surface. The reverse trends occurred on the Ag(110) surface.

Optically active sum frequency generation (OA-SFG) spectra of a series of chiral amino acid molecules are simulated with the dipole length and dipole velocity formalisms using the sum-over-states theory based on ab initio restricted Hartree-Fock (RHF/6-311++G^**) and configuration interaction singles (CIS/6-311++G^**) quantum chemistry calculations. OA-SFG spectra calculated by the dipole velocity method accurately reproduce the experimental relative intensity of OA-SFG spectra of amino acids, but the dipole length simulation did not. This is because of the origin-sensitivity of dipole length formulations. This study shows that it is preferable to use the dipole velocity method over the dipole length method to simulate OA-SFG spectra.

The molecular structure of the ground electronic state (X²Σ⁺) of ³⁵ClF^- and ³⁷ClF^- molecular ions have been calculated using single and double substitution quadratic configuration interaction calculations with the triple contribution [QCISD(T)] method and the simple and double excitation coupled-cluster theory with noniterative treatment with the triple excitations [CCSD(T)] method in combination with the correlation consistent basis sets aug-cc-pVXZ (X=D, T, Q, 5). Basis set extrapolation procedures were employed to estimate the complete basis set limit using results obtained with the CCSD(T) method. The analytical potential energy curves for the ground state of the systems were determined by fitting the data of single point energy scans that were calculated at the CCSD(T)/aug-cc-pVXZ (X=D, T, Q, 5) level of theory. The obtained potential energy curves correctly described the configuration and dissociation energy of the molecular ion and was well reproduced by the Murrell-Sorbie function. The corresponding spectroscopic parameters for the ground states of ³⁵ClF^- and ³⁷ClF^- molecular ions were also deduced. Parallel computations were carried out for the neutral ClF radical on the same level of theory. The results were in od agreement with available experimental data. The consistency between our results and previously reported experimentally determined values demonstrated the feasibility of the theoretical approach performed in this work. The optimized equilibrium geometric parameters were further used to derive the electron affinities of the neutral ClF radical. The vertical detachment energy of ClF^- was also determined. Based on computation results for ClF^-, the vibrational levels and corresponding molecular constants for the X²Σ⁺ states of ³⁵ClF^- and ³⁷ClF^- molecular ions were obtained by solving the radical Schr?dinger equation of the nuclear motion.

Density functional theory (DFT) and time-dependent DFT (TDDFT) were used to study the photophysical properties of N-butyl-4,5-di[2-(phenylamino)ethylamino]-1,8-naphthalimide, a ratiometric fluorescent sensor for Cu(II). The geometric structures of the compounds at the ground state were optimized by DFT. Combined with natural bond orbital (NBO) analysis, the binding characteristics of the chemosensor molecule coordinated with a Cu(II) ion were identified. The excitation states of the compounds were investigated and the internal charge transfer (ICT) mechanism was elucidated by theoretical calculations. The results indicated that the coordinated Cu(II) ion induced the dehydrogenation of naphthylamine. The negatively-charged amino N atom then formed a C＝N double bond with the naphthalene ring, extending the conjugation of the system. The nonbonding electron of N was transferred to the unoccupied d orbital of Cu(II), preventing fluorescence quenching by paramagnetic Cu(II). It was proposed that in the excited state, n→π^* electron transfer from the amino N to the naphthalene ring led to internal charge transfer and resulted in the red shift of fluorescence.

The isomerization mechanism of xylene over H-ZSM-5 molecular sieve has been examined using the density functional theory (DFT) and our own-N-layered integrated molecular orbital+molecular mechanics (ONIOM) methods. The structures of intermediate species and transition states are described. The adsorption of reactant and desorption of product significantly affect the tendency of xylene to isomerize. Calculated activation energies suggest that isomerization occurs during the formation of meta-xylene within the extended pore structure of H-ZSM-5 molecular sieve. However, the produced meta-xylene is retained within the pore because of a high desorption energy, and further isomerization to form para-xylene is kinetically favorable. The acid sites within the pores of the molecular sieve allow selective formation of para-xylene. On the external surface of H-ZSM-5 molecular sieve, which lacks the steric constraints of the extended pore structure, xylene isomerizes to form meta-xylene, which can readily desorb from the active site. Such non-selective isomerization decreases the selectivity for para-xylene. Thus, external surface modification of H-ZSM-5 molecular sieve should suppress the non-selective isomerization of xylene, thereby increasing the selectivity for para-xylene by restricting isomerization to inside the pores of the molecular sieve. Calculated relative reaction rate constants for xylene isomerization also indicate that xylene isomerization occurring on the external surface of H-ZSM-5 with meta-xylene as the product has the highest reaction rate. The selectivity for para-xylene is decreased as the reaction temperature is increased.

Spinel LiMn₂O₄ materials doped with tetravalent cations Ge⁴⁺ and Sn⁴⁺ were synthesized through solid-state reaction. Analysis of the materials by X-ray diffraction (XRD) and scanning electron microscopy (SEM) suggested that Ge⁴⁺ ions occupied octahedral sites by substituting Mn⁴⁺ ions in the spinel structure to form the solid solution LiMn_2-xGe_xO₄ (x=0.02, 0.04, 0.06), while Sn⁴⁺ ions were present at the surface of the spinel LiMn₂O₄ as SnO₂. The substitution of Mn⁴⁺ with Ge⁴⁺ could suppress the long-range ordering of the Li⁺ ions in the spinel LiMn₂O₄, enhancing its stability. SnO₂ on the surface of LiMn₂O₄ could reduce the acidity of the liquid electrolyte, suppressing acid etching of the LiMn₂O₄ active material. Galvanostatic charge/ discharge tests showed that both Ge⁴⁺ and Sn⁴⁺-modified spinel LiMn₂O₄ materials exhibited significantly higher capacity retention than LiMn₂O₄. The increased capacity retention should benefit the application of spinel LiMn₂O₄ as a cathode material for lithium-ion batteries.

A series of supported silver salts of heteropolyacid Ag_xH_3-xPW/SiO₂ (x=0.5, 1.0, 1.5, 2.0, 2.5, 3.0) were synthesized and showed high reactivity and stability in tetrahydrofuran polymerization, which were due to the salts' insolubility in polar solvent. The amount of Ag ion replaced in the salt and the amount of the salt loaded on the silica significantly influenced the catalytic performance. Change in the Ag content of the supported silver salt altered the crystal phase composition of the silver tungstophoric acid and catalyst's acid strength. The Ag_xH_3-xPW/SiO₂ catalyst had the highest acid strength and the highest polymerization activity when x=2.0. When the Ag₂HPW loading was 30% (mass fraction), the catalyst exhibited the best dispersion and highest activity for the polymerization of tetrahydrofuran. Compared with the conventional silica supported heteropolyacid (HPW/SiO₂) catalyst, the present 30%Ag₂HPW/SiO₂ displayed excellent reusability, with its reactivity only slightly declining after 4 reuses. Through the introduction of the Ag ion, the stability of the novel supported 30%Ag₂HPW/SiO₂ was significantly improved and the obtained polymer product, polytetrahydrofuran, had a stable average molecular weight.

Bismuth/zirconium gallate (Gal-BiZr) was synthesized from gallic acid, bismuth nitrate, and zirconyl nitrate firstly, and characterized by elemental analysis, X-ray fluorescence (XRF), and Fourier transform infrared (FTIR) spectroscopies. The thermal behavior and decomposition mechanism of Gal-BiZr in a temperature-programmed mode were investigated by thermogravimetric (TG) analysis, differential scanning colorimetry (DSC), and condensed phase thermolysis/FTIR techniques. The decomposition products of Gal-BiZr are Bi₂O₃, ZrO₂, and C. Samples of propellants containing Gal-BiZr were prepared by extrusion technology, and the effect of Gal-BiZr on double-base (DB) propellant combustion properties was investigated. Gal-BiZr exhibits od catalytic behavior in the combustion of DB and Hexogeon (RDX)- CMDB propellants.

P(NIPAM-co-AA) copolymer microgels with temperature and pH sensitivities were synthesized by copolymerization of N-isopropylacrylamide (NIPAM) and acrylic acid (AA). Ag/P(NIPAM-co-AA) composite microspheres were prepared via in-situ reduction using ethanol as a reducing agent, based upon a polymer microgel template method. The morphology, composition, and catalytic properties of the prepared composite microspheres were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-visible (UV-Vis) spectrophotometry. It was demonstrated that the Ag/P(NIPAM-co- AA) composite microspheres had an uneven surface structure. The confinement effect of the template microgels significantly improved the dispersion and stability of the loaded silver particles. In addition, the obtained composite materials exhibited od catalytic activity for the reduction of 4-nitrophenol (4-NP). The observed catalytic activity was related to the swelling and shrinking behavior of the microgel network structure. The catalysis of 4-nitrophenol reduction was controlled by adjusting the thermo-sensitivity of the polymer template.

Melamine and its polymer (g-C₃N₄) were used as ligands to prepare Fe-N/C electrocatalysts for the oxygen reduction reaction (ORR) by an impregnation method. The composition, morphology and electrocatalytic activity of the catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and electrochemical measurements. The Fe-N/C catalyst using g-C₃N₄ as a complex ligand showed higher activity in the ORR than that with melamine. The formation of quaternary N active sites on the surface of the catalyst during heat treatment helps to improve their performance in the ORR.

Ru-Fe₃O₄/γ-Al₂O₃ was synthesized by stepwise impregnation method and applied to the in-situ liquid phase selective hydrogenation of 3,4-dichloronitrobenzene (3,4-DCNB). The nanoparticle size and distribution, metallic crystalline constitution, surface structure parameters, and adsorption species were systematically characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, N₂ adsorption-desorption (BET), and X-ray photoelectron spectroscopy (XPS). The Ru-Fe₃O₄/γ-Al₂O₃ catalyst was investigated using the in-situ liquid phase hydrogenation of 3,4-DCNB as probe reaction, the effect of different reaction conditions and different synthetic factors on the catalytic properties was studied. Experimental results showed that the catalytic properties of the Ru-Fe₃O₄/γ-Al₂O₃ catalyst were significantly influenced by its Fe₃O₄ content, under the optimum condition of 473 K, 3.0 MPa, 2% (w) 3,4-DCNB concentration with 75% ethanol and 25% water, the Ru-Fe₃O₄/γ-Al₂O₃ catalyst with Ru and Fe mass fractions of 2% and 6% exhibited the highest activity and stability, with 100% conversion of 3,4-DCNB, 96.4% selectivity of 3,4-dichloroaniline (3,4-DCAN), and this catalyst could be stabilized for more than 200 h. The main reason for the deactivation of the catalyst is CO coverage on active centers, and the poisoning-deactivated catalysts were regenerated by water-gasshift (WGS) reaction and Fischer-Tropsch synthesis (FTS), which employ Fe₃O₄ modified Ru/Al₂O₃ as catalyst due to its high efficiency of CO transformation. Carbon deposition on the catalyst surface is the reason second only to carbon monoxide poisoning, and this could be removed through calcination. Crystalline phase change and nanoparticles aggregation may cause partial deactivation, and investigation of the mechanism and catalyst regeneration are in progress.

Ni-Co/La₂O₃-γ-Al₂O₃ catalysts for biogas reforming were prepared by conventional incipient wetness impregnation and pretreated first by hydrogen reduction and then by pure carbon monoxide, methane and carbon dioxide, respectively. The effect of pretreatment route on the biogas reforming performance of the catalysts was investigated. The catalysts were characterized with X-ray diffraction (XRD), thermogravimetric and differential scanning calorimetry (TG-DSC), and transmission electron microscopy (TEM), and the relationship between the performance and the structural properties of the catalysts was investigated. The results indicated that, compared with the performance of catalysts pretreated by the traditional hydrogen reduction, the performance of catalysts pretreated by hydrogen and carbon monoxide did not change significantly, while the performance of catalysts pretreated by hydrogen and methane deteriorated obviously. Nevertheless, the performance of catalysts pretreated by hydrogen and carbon dioxide was dramatically enhanced and the long adjustment period of the biogas reforming catalysts was basically eliminated. The characterization results showed that the active metal particle size of the catalysts pretreated by hydrogen and carbon dioxide was smaller on average and distributed more evenly and much more narrowly, which notably enhanced the catalysts' carbon resistance and prolonged the catalysts' longevity.

Nanosized cuprous oxide (Cu₂O) was used to modify the surface of γ-Bi₂MoO₆, resulting in highly efficient visible-light-responsive Cu₂O/γ-Bi₂MoO₆ composite photocatalysts. The obtained photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), and UV-Vis diffuse reflectance spectrum (UV-Vis-DRS) to determine their phase structures, micromorphologies, and light absorption properties. The important role of surface-modified Cu₂O in improving the photocatalytic activity of γ-Bi₂MoO₆ under visible light irradiation was studied using the degradation of methylene blue (MB). The results showed that Cu₂O nanoparticles with average size of ~10 nm modified the surface of the γ-Bi₂MoO₆. The nanoparticles delivered both an obvious red-shift of absorption threshold and intensity of the γ-Bi₂MoO₆, as well as enhanced separation efficiency of photogenerated carriers, thereby leading to significant enhancement in photocatalytic activity. When the amount of Cu₂O was 1.5%, the photocatalytic activity of the Cu₂O/γ-Bi₂MoO₆ composite photocatalyst was 6.4 times higher than that of pristine γ-Bi₂MoO₆.

A nanofilm (TES-SAMs) was prepared by self-assembly of 6-(3-triethoxysilylpropylamino)-1,3, 5-triazine-2,4-dithiol monosodium (TES) on a sintered NdFeB surface. A nano composite film (TES-ATP) was then prepared on the TES-SAMs surface by a self-developed polymer plating technique using 6-(N-allyl-1,1,2,2-tetrahydroperfluorodecylamino)-1,3,5-triazine-2,4-dithiol monosodium (ATP). The surface of the TES-SAMs and TES-ATP were characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, spectroscopic ellipsometry, atomic force microscopy (AFM), and contact angle measurements. A UMT-2 tribometer was used to investigate their micro-tribological properties. The experimental results showed that the thicknesses of TES-SAMs and TES-ATP were 5.08 and 29.78 nm, respectively. The surface free energy of TES-ATP and TES-SAMs decreased from 73.13 mJ·m^-2 for the substrate to 10.19 and 63.39 mJ·m^-2, respectively. The contact angle of distilled water on TES-ATP was 123.5° , indicating transformation from a hydrophilic surface to a hydrophobic one. The friction coefficient was effectively reduced from 0.71 for the substrate to 0.22 for TES-SAMs and 0.12 for TES-ATP. In addition, the TES-ATP composite film possessed excellent anti-wear ability. Thus, the present TES-ATP composite film provides a novel approach to solving tribological issues in micro-electro-mechaanical system(MEMS).

The elimination of bisphenol A (BPA) from aqueous solution by adsorption on graphene oxide ( ) was investigated. The maximum adsorption capacity (q_m) of for BPA estimated from the Langmuir isotherm was 87.80 mg·g^-1 at 25℃. The required contact time to reach adsorption equilibrium was about 30 min, which was much shorter than that of activated carbon. The adsorption kinetics and isotherm data fitted well with the pseudo-second-order kinetic model and the Langmuir isotherm, respectively. Neutral pH and low solution temperature were favorable for adsorption, whereas the presence of NaCl in the solution was unfavorable. The had od recyclability and could be reused several times with a slight decline in adsorption ability. Both hydrogen bonding and π-π interaction were thought to be responsible for the adsorption of BPA on . The excellent adsorption capacity and high adsorption rate of result from its sheet-like structure and the abundant oxygen-containing groups on its surface. Although q_m of for BPA is lower than that of graphene, has the benefits of large scale production, a hydrophilic surface with plenty of oxygen-containing groups, and od dispersion in water. Therefore, can be regarded as a od potential adsorbent for water treatment.

The adsorption and decomposition of NO₂ on Ag/Pt(110) bimetallic surfaces have been investigated by Auger electron spectroscopy (AES) and thermal desorption spectroscopy (TDS). At room temperature, NO₂ under es dissociative chemisorption on Ag/Pt(110) bimetallic surfaces, forming chemisorbed NO(ads) and O(ads). Upon heating, NO(ads) under es both desorption from the surface and further decomposition. At 500 K, NO₂ chemisorbs dissociatively on Ag/Pt(110) bimetallic surfaces, forming O(ads). Electron transfer occurs from Pt to Ag, therefore, the presence of Ag on Pt(110) surface weakens the binding energy of O(ads) with the surface and decreases the temperature required for the recombinative desorption of O(ads) from the surface. We observed the formation of a Ag/Pt(110) alloy structure that exhibits catalytic activity towards NO₂ decomposition similar to that of Pt(110)-(1×2) but with a binding energy towards O(ads) much lower than that of Pt(110)-(1×2). Such a Ag/Pt(110) alloy structure may be active in catalyzing the direct decomposition of NO_x at relatively low temperatures.

Molecular dynamics (MD) simulations and free energy calculations were integrated to investigate substrate-enzyme dynamic interactions during the unbinding of phenylsulfonamide from carbonic anhydrase II (CA II). The potential of mean force (PMF) along the unbinding pathway shows that a special ligand-binding state exists, and the electrostatic interaction dominates the ligand?s binding with CA II. The analysis of trajectories reveals that, apart from the zinc ion, the key residues in the unbinding pathway, Leu198, Thr199, and Thr200, prevent the substrate?s unbinding from the enzyme by hydrogen bonding with the sulfanilamide group of the substrate. The present results are of direct significance for the in-depth understanding of the sulfonamide-CA II binding process and related drug design.

Inhibition of protein aggregation during protein refolding is a fundamental issue in the production of recombinant therapeutic proteins. It has recently been experimentally found that like-charged ion-exchange resin can suppress the aggregation of folding intermediates through electrostatic repulsion. However, the microscopic understanding of this process is far from adequate, and it is difficult to examine the microscopic process using experimental approaches. Molecular dynamics (MD) simulation is a powerful tool which can provide clear microscopic information in a direct manner. Therefore, in the present study, a model of an electrostatically repulsive surface is constructed to simulate the like-charged ion-exchange resin. The distribution of lysozyme molecules near the surface is then investigated using MD simulation with all-atom (AA) models and the effect of the charge number of the surface is examined. It is found that the protein is excluded from the surface by electrostatic repulsion. During this process, the protein molecule becomes standing, where the dipole of the protein is perpendicular to the surface. When the protein moves far from the surface, diminished oriented alignment is observed due to the decreased electrostatic repulsion from the surface. It is also found that better oriented alignment on the surface occurs with higher charge number. The simulation results thus provide microscopic information about the alignment of protein molecules near an electrostatically repulsive surface, and are expected to be helpful for investigation of protein refolding on charged surfaces and the molecular interactions involved.

Flexible oriented TiO₂ nanowhisker films with large aspect ratios were hydrothermally prepared in 1 mol·L^-1 NaOH solution from Ti film deposited by magnetron sputtering on a flexible stainless steel substrate. The influence of the Ti film deposition conditions on the resulting TiO₂ nanowhisker films was investigated. We also systematically studied the effects of the hydrothermal parameters on the nanowhisker films and their growth mechanism. The samples were characterized by field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), and high resolution transmission electron microscopy (HRTEM). The results showed that nanowhisker film prepared from Ti film deposited at 600 ° C had stronger adhesion to the substrate compared with that prepared from Ti film deposited at room temperature. The as-prepared TiO₂ nanowhiskers were single crystalline anatase and were the result of transformation of Ti into Na₂Ti₂O₄(OH)₂ and H₂Ti₂O₅·H₂O. The nanowhiskers took shape during the hydrothermal synthesis, preferably oriented parallel to (100) crystal face of Na₂Ti₂O₄(OH)₂, and experienced splitting conversion from nanobelts to nanowire harnesses and nanowires. The formation of vertical nanowhisker films was ascribed to a cooperative effect of the dilute NaOH solution and the higher hydrothermal temperature (220 ° C). The photoelectrochemical properties of the films were investigated in Na₂SO₄ solution, and the results showed that the as-prepared TiO₂ nanowhisker film exhibited better photoelectrochemical properties than those of zero-dimensional nanoparticle films and two-dimensional nanobelt films, indicating a od potential for practical application.

Nanoporous ld films were prepared by immersing Au-Ag alloy films with a thickness of ca 60 nm sputtered on glass substrates in nitrate acid to remove the Ag component. Using a home-made wavelength-interrogated surface plasmon resonance (SPR) sensor platform, the influence of the immersion time on the SPR properties of the nanoporous ld film was investigated. If the nanoporous ld film was immersed in aqueous solution, SPR was not detected in the wavelength range from 400 to 900 nm. However, when the nanoporous ld films were exposed to air, a strong SPR absorption peak was detected in the same spectral range. The peak position gradually moved to longer wavelength as the immersion time extended. The SPR of the nanoporous ld film in air enables the film to be used for in situ monitoring of gas-phase molecular adsorption and ex situ detection of biochemical molecules adsorbed in the liquid phase. Ex situ detection of three kinds of small molecules (L-glutathione, L-cysteine, and cysteamine) adsorbed to the nanoporous ld film was fulfilled. The results were compared with those obtained using a conventional SPR chip with a dense ld film, revealing that the nanoporous ld films have a higher sensitivity and lower detection limit than the dense ld layer because of their larger surface area. Adsorption of ethanol molecules in the gas phase was monitored in situ, and the time required to reach adsorption equilibrium was about 160 min.

Highly crystalline, porous ZnO sheets were prepared from chemically-deposited zinc sulfate hydroxide hydrate (ZSH) sheets by sintering at 1000 ℃. The formation mechanism of ZSH in Zn²⁺- hexamethyltetramine (HMT) precursor system, the transformation process of ZSH to ZnO, and the crystalline, microstructural and optical properties of the ZnO sheets were investigated. The porous ZnO sheets possessed a well-defined hexa nal shape with controllable size (10-50 μm) and thickness (200-500 nm), high crystallinity, and strong ultraviolet photoluminescence without detectable defectrelated visible emission. Submicron-sized pores (100-500 nm) and poly nal or irregular ZnO particles resulting from the limited mass transport during high temperature sintering were observed in the ZnO sheets. Analysis of the formation mechanism indicated that the high affinity of SO₄^2- for Zn²⁺ was responsible for the formation of ZSH in the Zn²⁺-HMT precursor system, and the thermolysis of ZSH affected the morphology and microstructure of the ZnO sheets. This work reveals a facile route to porous ZnO nanostructures with od crystallinity and optical properties, which make them suitable for application in catalysis, and photo and/or electrical devices.

Templating is one of the most important methods for preparation of inorganic hollow micro/ nano spheres. We prepared monodisperse polystyrene (PS) microspheres having a diameter of 620 nm by the emulsion polymerization of styrene. Sulfonated polystyrene (PSS) microspheres were used as a template, through electrostatic adsorption of anions and cations, for modification with Sn²⁺ from SnSO₄ precursor. The core-shell composite structures thereby produced through Sn²⁺ hydrolysis in an ethanolwater medium were calcined at high temperature to remove PSS and to obtain SnO₂ hollow micro/nano spheres. We investigated the effects of precursor concentration, amount of surfactant, reaction time, and templates choice. Scanning electron microscopy (SEM), X-ray diffraction (XRD), infrared (IR) spectroscopy, thermogravimetric analysis (TGA), H₂ temperature programmed reduction (H₂-TPR), Brunauer-Emmett-Teller (BET) measurement, and other technical probes were used to detect the structure and properties of the prepared SnO₂ hollow micro/nano spheres, and compared them with those of solid SnO₂. BET and H₂-TPR showed that the hollow SnO₂ micro/nano spheres had improved specific surface area, surface oxygen vacancies, and oxidation activity. We inferred the growth mechanism of the core-shell structure from IR spectroscopy and XRD pattern and optimized the simple and reasonable synthesis procedure to obtain SnO₂ hollow micro/nano spheres which had smooth surface, compact structure, and well controlled cladding thickness.