Raman spectroscopy has been widely used as a non-destructive testing and molecular recognition technology, providing fingerprint information for chemical and biological molecular structures. One type of out-of-plane bending vibration observed in Raman spectroscopy is named the‘wagging vibration’. The Raman signal of the wagging mode is very sensitive; not only the vibrational frequency but also the Raman intensity depends strongly on environment factors. In this report, density functional theory (DFT) calculations are used to study the equilibrium structures, binding interactions, and Raman spectra of vinylamine and aniline as well as their complexes with silver clusters and water clusters. Vinylamine-silver and aniline-silver clusters were used to simulate the interactions of the molecules adsorbed on silver surfaces, while vinylamine-water and aniline-water clusters were used to investigate the hydrogen bonding interactions of vinylamine and aniline with water clusters. Our calculated results show that the Raman signal of the amino wagging mode strongly depends on the hydrogen bonding interaction of the nitrogen lone pair in the amino group with the O―H bond of water. Increasing the size of the water clusters causes a large blue shift and considerable enhancement in the intensity of the wagging vibration. When the polarized continuum model was used to consider the solvation effect, the electrostatic interaction contributing to the hydrogen bond was weakened. In this case, the simulated Raman spectra were similar to each other. For vinylamine and aniline interacting with silver clusters, the Raman signals of the amino wagging vibration were changed by the weak binding interaction, revealing the relationship between the abnormal signal of wagging vibrations and the weak interaction in p-π-conjugated systems.

We analyzed the change of hydrogen bonding between Br^- and imidazolium cations when the ionic liquid 1-butyl-3-methylimidazolium bromide ([BMIM]Br) was gradually mixed with 1-butyl-3- methylimidazolium tetrafluoroborate ([BMIM] [BF₄]) using X-ray absorption fine structure (XAFS) and ultraviolet absorption spectroscopies. As the content of [BMIM][BF₄] increased, the intensity of the K-edge main peak of Br reduced in X-ray absorption near edge structure (XANES) spectra, and the absorption edge moved 0.9 eV to lower energy. Meanwhile, the radial structure given by extended X-ray absorption fine structure (EXAFS) indicated that the distribution number reduced and average hydrogen bond length increased. UV spectra showed a clear blue shift and peaks decreased in intensity as the content of [BMIM][BF₄] increased. All of these results indicate that more negative charge was transferred to Br^- as the content of [BMIM][BF₄] increased. The data obtained from quantum chemical calculations also support this conclusion.

To evaluate the thermal safety of energetic materials (EMs) using the critical rate of temperature rise of thermal explosion (dT/dt)_Tb and obtain basic data used to calculate (dT/dt)_Tb, nine expressions to calculate (dT/dt)_Tb for EMs were derived from Semenov thermal explosion theory and nine autocatalytic reaction rate equations, dα/dt=Aexp(-E/RT)α(1-α) (I), dα/dt=Aexp(-E/RT)(1-α)ⁿ(1+K_catα) (II), dα/dt=Aexp(-E/RT)[α^a-(1-α)ⁿ] (III), dα/dt=A₁exp(-E_a1/RT)(1-α)+A₂exp(-E_a2/RT)α(1-α) (IV), dα/dt=A₁exp(-E_a1/RT)(1-α)^m+A₂exp(-E_a2/RT)αⁿ(1-α)^p (V), dα/dt=Aexp(-E/RT)(1-α) (VI), dα/dt=Aexp(-E/RT)(1-α)ⁿ (VII), dα/dt=A₁exp(-E_a1/RT)+A₂exp(-E_a2/RT)(1-α) (VII) and dα/dt=A₁exp(-E_a1/RT)+A₂exp(-E_a2/RT)α(1-α) (IX), using reasonable hypotheses. A method to determine the kinetic parameters in the nine autocatalytic decomposition reaction rate equations and (dT/dt)_Tb of EMs when autocatalytic decomposition converts into thermal explosion from difference scanning calorimetry (DSC) curves at different heating rates (β) was presented. The onset temperature (T_e0) corresponding to heating rate β→0, the critical temperature of thermal explosion (T_b) and the conversion degree (α_b) corresponding to T_b used in the calculation of (dT/dt)_Tb were obtained from analysis of DSC curves. The kinetic parameters of the autocatalytic decomposition reactions in Eqs.(I) and (VI), and Eqs.(II)-(V), (VII)-(IX) were estimated by the linear least-squares method and trust region approach, respectively. The values of (dT/dt)_Tb for EMs were obtained from basic DSC data. Results show that (1) under non-isothermal DSC conditions, the autocatalytic decomposition reaction of nitrocotton (NC) (13.54% N) can be described by the apparent empiric-order equation dα/dt=10^15.82exp(-170020/RT)(1-α)^1.11+10^15.82exp(-157140/RT)α^1.51(1-α)^2.51; (2)The value of for NC (13.54% N) when autocatalytic decomposition converts into thermal explosion is 0.103 K·s^-1.

Based on the laser pulse output from a femtosecond regenerative amplifier and optical parametric amplifier (OPA), a broadband time-resolved coherent anti-Stokes Raman scattering (CARS) setup was assembled. Using this setup, the relationship of hydrogen CARS spectra to its amount in a mixture with air and the relevant detection time-delay were studied. Hydrogen CARS spectra without nonresonant background interference were obtained by adjusting the detection time-delay. The observed CARS intensity exhibited a linear relationship with the square of hydrogen concentration, which is consistent with the theoretical prediction. The signal-to-noise ratio showed that when the pressure of hydrogen-air mixed gas was 0.1 MPa, the detection limit of our setup was less than 0.2%. Using this setup, the hydrogen production kinetics of a platinum(II) terpyridyl acetylide molecular-cobalt catalysttriethanolamine (TEOA) system was studied. The kinetic mechanism of hydrogen production was discussed by considering the effect of changing pH. The results indicate that a high proton concentration will reduce the hydrogen production efficiency. This can be attributed to the inhibition of hydrolysis of TEOA under acidic conditions, because it is the electron and proton donor in this hydrogen production system.

The quantitative structure-activity relationship (QSAR) approach was used to predict the activity of two different scaffolds (benzoisothiazole and benzothiazine) of 89 non-nucleoside inhibitors of hepatitis c virus (HCV) NS5B polymerase. Two selection methods, linear stepwise regression analysis (LSRA) and genetic al rithm-partial least squares (GA-PLS), were used to select appropriate descriptor subsets for QSAR modeling with linear models. The genetic al rithm-support vector machine (GA-SVM) approach was first used to build nonlinear models with six LSRA- and seven GA-PLS-selected descriptors. Three QSAR models built with the six LSRA-selected descriptors gave correlation coefficients of 0.958-0.962 for the training set. GA-SVM provided the highest prediction accuracy of the models of 0.962. Three QSAR models built with the seven GA-PLS-selected descriptors gave correlation coefficients of 0.918-0.960 for the training set, of which the partial least squares (PLS) model was the best (0.960). The investigated models gave satisfactory prediction results and can be extended to other QSAR studies.

The geometries and electronic properties of armchair MoS₂ nanoribbons were investigated by the first-principles method based on density functional theory. It was found that the stability and electronic properties of armchair MoS₂ nanoribbons sensitively depend on edge modification. Increasing the number of hydrogen atoms on the edge caused the nanoribbons to become more stable and transition between indirect-gap semiconductor, semi-metal and direct-gap semiconductor. The band structure and densities of states of the nanoribbons indicated that low energy bands contributed to edge states. Different hydrogen adsorption patterns on each edge induce two kinds of edge state on the nanoribbons and these two kinds of edge state have little effect on each other. The relationships between the bandgap and width of three types of nanoribbons were studied. Nanoribbons terminated with zero or eight hydrogen atoms in each unit cell have a bandgap that oscillates with width in a period of three, while the bandgap changes nonperiodically in those terminated with four hydrogen atoms.

Water transport in nanopores is important for many biological processes and the design of nanodevices. It has been demonstrated that water molecules are transported through a (6,6)-type carbon nanotube (CNT) by forming single-file chains. However, a controllable water flow through a CNT remains difficult to achieve. In this paper, we investigated how to control the net flux of water molecules transported through a CNT and the on-off gating behavior of the CNT using an ortho nal electric field. With a 200 MPa pressure difference acting on the top of the first layer of water molecules as the driving force, the net flux of water molecules decreased linearly as the ortho nal electric field strength (E) increased from 1 to 3 V· nm^-1. When E increased over 3 V·nm^-1, the flow of water molecules through the CNT was turned off and the net flux was almost zero. Both the orientation of water dipoles and flipping frequency were strongly correlated with the water occupancy in this case.

Zeolites are microporous materials that have been widely used in various chemical industries. Zeolite structure prediction involves building feasible zeolite frameworks on computers, and can be used as a tool to determine the structures of synthesized zeolites and to identify promising synthetic candidates for future rational synthesis. Although many approaches for zeolite structure prediction have been developed, none of them has proved to be efficient at generating chemically feasible structures. To solve this problem, we developed the computer program FraGen to predict inorganic crystal structures. FraGen is capable of generating atoms in a given unit cell, adjusting the locations of atoms through the parallel tempering Monte Carlo method, and producing chemically feasible crystal structures. In this work, starting from the structure of zeolite AET, we use FraGen to predict a series of novel zeolite structures by controlling the Wyckoff site symmetry of each atom specifically. Compared with previous prediction methods, FraGen can generate more structures that are chemically feasible.

Density functional theory calculations are used to investigate the surface structure and electric conductivity of the (010) surface of LiFePO₄ coated with graphene or graphene-like B-C-N. The calculations indicate that the interaction between the coating and LiFePO₄ (010) surface improves the electric conductivity of the LiFePO₄ (010) surface. The band gap decreases from 3.3 to 2.1 eV when the LiFePO₄ (010) surface is coated with graphene. When the LiFePO₄ (010) surface is coated with graphene-like B-C-N, the valence band maximum and conduction band minimum are still dominated by Fe-3d orbitals; however, two in-gap states with an interval of 0.6 eV appear in the band gap, which are attributed to the bonding interaction between graphene-like B-C-N and the LiFePO₄ (010) surface.

The mechanism of the O₂ activation by the protocatechuate 3,4-dioxygenase was investigated using density functional calculations. In the initial complex, the ultrafast formation of the sextet ⁶1 was probably the result of electron-exchange-induced intersystem crossing, and Fe d_z:O₂ π^*(z) was the dominant exchange pathway, with an overlap of d_z: O₂π^*(z) was dominant exchange pathway with the overlap of S_ij=ád_z α|π^*(z) β>=0.3758 at an Fe―O bond length of 0.2487 nm. Two coexisting effects, electron spin exchange coupling and spin-orbit coupling (SOC) in the sextet ⁶1, are responsible for formation of the quartet state ⁴1 from the sextet ⁶1. The exchange interaction competes with the SOC interaction as a driving force for spin conversion. The calculated results show that the latter is the dominant factor, because of the larger SOC constant (353.16 cm^-1). In cleavage of the O― O bond, electron transfer from the protocatechuate (PCA) highest occupied molecular orbital (HOMO) plays a vital role. The Fe center of the non-heme enzyme is a buffer to transfer an electron pair from the PCA HOMO to O₂.²²²

Nanocomposites of partially reduced graphene oxide ( )-K₂Mn₄O₈ were synthesized via a hydrothermal process at different temperatures and molar feed ratios of to KMnO₄. X-ray diffraction (XRD) analysis confirmed that both α-MnO₂ and a novel crystal phase of K₂Mn₄O₈ were obtained under the investigated hydrothermal conditions. X-ray photoelectron spectroscopy (XPS) revealed diverse changes of the oxygen-containing functional groups on the surface of depending on temperature and molar feed ratio. The microstructure of the composites was studied to help understand their electrochemical properties. A flaky structure of reduced graphene oxide (r ) covered by nanoparticles was observed by scanning electron microscope (SEM), which was considered to be favorable for charge transfer. The capacitive properties of the composites were compared using cyclic voltammograms and galvanostatic charge-discharge measurements. The specific capacitance of the optimal sample was calculated to be 251 F·g^-1 with an energy density of 32 Wh·kg^-1 and a power density of 18.2 kW·kg^-1 in 1 mol·L^-1 Na₂SO₄ electrolyte at a current density of 1 A·g^-1 between 0 and 1 V. Moreover, the capacitance retention ratio of this sample remained at 88% after 1000 cycles at a high current density of 5 A·g^-1.

Graphene oxide/polypyrrole ( /PPy) intercalation composite was successfully prepared via in-situ chemical oxidative polymerization of pyrrole monomers by using methyl orange (MO) as a template agent. The morphology and microstructure of the composite were characterized by X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). In addition, the electrochemical properties of the composite material were investigated by cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy techniques in two different aqueous electrolytes (1 mol·L^-1 Na₂SO₄ and 1 mol·L^-1 H₂SO₄). The results indicated that the /PPy intercalation composite displayed considerable specific capacitance in both neutral and acid electrolytes, which is attributed to taking full advantage of the superior properties and synergy of graphene oxide and polypyrrole. The /PPy intercalation composite exhibited the specific capacitance of 449.1 and 619.0 F·g^-1 in the Na₂SO₄ and H₂SO₄ electrolytes, respectively, at a current density of 0.5 A·g^-1. This is significantly higher than the corresponding specific capacitance of pure PPy. After 800 cycling test, the specific capacitance of the composite remained about 92% and 62% of the initial capacitance in the two different electrolytes, respectively. A higher initial capacitance was obtained in the acidic electrolyte, but the composite showed better electrochemical cyclic stability in the neutral electrolyte.

The electrochemical behavior and thermodynamic properties of MgCl₂ dissolved in LiCl-KCl eutectic melts in the temperature range of 723-908 K were investigated. Cyclic and square wave voltammetry experiments indicated that the reduction of Mg ions into Mg metal occurred in a single step and involved exchange of two electrons. The diffusion coefficient (D) of Mg(II) was determined by the Berzins-Delahay equation and the Arrhenius law was validated by plotting lgD versus T^-1 for the reduction of Mg(II). Open circuit chronopotentiometry was used to determine the equilibrium potential of Mg(II)/Mg(0). The standard apparent potentials of the Mg(II)/Mg(0) system and the activity coefficients of Mg(II) in LiCl-KCl eutectic melts based on a pure supercool reference state were calculated at several temperatures.

The electrochemical behavior of U(VI) extracted from an aqueous solution of uranyl nitrate by octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) in an ionic liquid was investigated. The hydrophobic ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C₄mimNTf₂) was used in this study. Using an equimolar series method, we found that CMPO and U(VI) formed a 3:1 molar complex during the extraction process. Cyclic voltammetry was used to investigate the electrochemical behavior of the U(VI)-CMPO complex in C₄mimNTf₂. The U(VI)-CMPO complex was found to be quasi-reversibly reduced to a U(V)-CMPO complex. The formal redox potential (E^Θ, vs Fc/Fc⁺) for the U(VI)/U(V) couple was determined to be (-0.885±0.008) V. Controlled-potential electrolysis of the extract gave a deposit on the surface of a platinum plate. X-ray photoelectron spectroscopy showed that the deposit contained only U(VI), U(IV), and oxygen, and the CMPO extractant and the ionic liquid were not trapped in the deposit.

We synthesized silver-copper (Ag-Cu) dendritic structures on Cu foil by electrodeposition and subsequent galvanic displacement reaction. The crystalline nature and morphology of the nanostructures were examined by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM), respectively. The morphology of the Cu precursor changed from rod to dendrite, and finally grew into foam as the overpotential was increased. When the Cu precursor was reacted with silver nitrate through galvanic displacement reaction, a foam-like precursor produced a denser, more uniform Ag-Cu dendrite. In addition, the concentration of silver nitrate solution had a considerable effect on the shape of the nanoparticles, with increasing concentration within a certain range promoting dendrite formation. The electrochemical properties of the Ag-Cu dendrite-modified electrode were characterized by linear sweep voltammetry and amperometric current-time curves. The reduction peak potential was about -0.25 V (vs a saturated calomel electrode (SCE)) in the electrolyte solution, which indicates that the as-synthesized Ag-Cu dendrites have favorable electroreduction activity towards hydrogen peroxide (H₂O₂). When an Ag-Cu dendrite was used as a sensor, the electrode exhibited a rapid response time of 3 s, a wide linear range of 0.1-12 mmol·L^-1 H₂O₂, and a remarkable sensitivity of 330.36 μA·(mmol·L^-1)^-1·cm^-2, which is particularly important to improve the accuracy of sensors.

A graded anode-supported solid oxide fuel cell (SOFC) with the structure porous Ni-yttria stabilized zirconia (Ni-YSZ)|microporous Ni-YSZ|YSZ|La_0.8Sr_0.2MnO₃ (LSM) was fabricated by a trilayer co-pressing-sintering method, and coating with an LSM cathode. Cu-CeO₂ was impregnated into the porous Ni-YSZ layer using nitrate/glycol precursors to act as an anti-carbon catalyst to fabricate a graded Cu-CeO₂-NiO-YSZ composite anode. The current-voltage (I-V), current-power (I-P), and long-term stability of the SOFC were tested using CH₄ or H₂ as fuels and air as an oxidant. The results show that the co-pressing-sintering layers possess a gradient pore structure with defect-free combination. The power density of SOFC supported by a graded Ni-YSZ anode is 284 mW·cm^-2, operated at 850℃ using H₂ as a fuel, but decreases to 143 mW·cm^-2 when the fuel is changed to CH₄. In contrast, the cell supported by a Cu-CeO₂-Ni-YSZ anode show the reverse behavior, increasing from 176 to 196 mW·cm^-2 when the fuel is changed from H₂ to CH₄ at 850℃. Under a 250 mA·cm^-2 load using CH₄ as the fuel, the output of the cell with a graded Ni-YSZ anode fluctuats and the cell is blocked after 10 h. At this point, carbon particles or fibers are observed in the anode layer by scanning electron microscopy (SEM). Conversely, the cell with a Cu-CeO₂-Ni-YSZ anode shows stable power output for 50 h or longer, and no carbon deposition was observed inside the anode.

The quartz-crystal microbalance technique was used to monitor the adsorption of glucose oxidase ( x) on bare Au, Au-electrodeposited Au (Au_ed/Au), multiwalled carbon nanotube (MWCNT)- modified Au (MWCNTs/Au), and Au-electrodeposited MWCNT-modified Au (Au_ed/MWCNTs/Au) electrodes. The mass of x at saturated adsorption was obtained in each case. The amperometric responses of these enzyme electrodes were examined, and the mass-specific bioactivities of the immobilized (adsorbed) x (MSBA_i) were evaluated through anodic potentiostatic detection of enzymatically generated H₂O₂ in the presence of glucose. The direct electrochemistry of adsorbed x was studied by cyclic voltammetry, to obtain the electroactivity percentage of the immobilized (adsorbed) x (EAP_i) in each case. We found that the amounts of enzyme adsorbed and the amperometric responses of these enzyme electrodes follow the order MWCNTs/Au > Au_ed/MWCNTs/Au > Au_ed/Au > Au; MSBA_i follows the order of Au > Au_ed/MWCNTs/Au > Au_ed/Au > MWCNTs/Au; and EAP_i follows the order of MWCNTs/Au > Au_ed/MWCNTs/Au > Au_ed/Au > Au. The experimental data are interpreted based on hydrophobic/hydrophilic interactions among enzyme molecules and the nanomaterials, as well as the amount of adsorbed x. It was also verified that the total enzymatic activity of all the electrode-adsorbed enzyme molecules is positively related to the amperometric responses of the enzyme electrodes. This work is useful in studying the immobilization of enzyme on nanomaterials and thus-prepared amperometric enzyme electrodes.

We report here the photovoltaic performance of a solar cell using poly-{[4,8-bis[(2-ethylhexyl) oxy]-benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]-alt-[3-fluore-2-(octyloxy)carbonyl-thieno[3,4-b]thiophene-4,6- diyl]} (PBDT-TT-F):[6,6]-phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM) as the photoactive layer in combination with a thin poly(3-hexylthiophene) (P3HT) film as a photosensitizing layer. PBDT-TT-F strongly absorbs light in the wavelength range of 550-700 nm, but it absorbs relatively weakly in the range of 350-550 nm. In contrast, a P3HT film shows intensive absorption ability in the 450-600 nm region, suggesting that the absorptions of these two materials complement each other to give a broad range. An organic solar cell with the structure indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene)- polystyrenesulfonic acid (PEDOT:PSS)/P3HT/ PBDT-TT-F:[6,6]-phenyl C₆₁-butyric acid methyl ester (PC₆₁BM)/LiF/Al was fabricated in which P3HT was deposited between the hole transporting layer (PEDOT: PSS) and bulk heterojunction (BHJ) photoactive layer (PBDT-TT-F:PC₆₁BM). This solar cell exhibited improved spectrum response in the wavelength range of 450-600 nm compared with one without a P3HT layer, which is attributed to the photosensitizing effect of the P3HT film. Optimization of the thickness of P3HT led to an increase of short-circuit current density (JSC) from 11.42 to 12.15 mA·cm^-2.

Core-shell structured Co@Pt/C electrocatalysts containing different mass fractions of Co to Pt, which are represented as 20% (w) Co@Pt(1:1)/C and 20% (w) Co@Pt(1:3)/C, were prepared by changing the ratio of metallic precursors using a successive reduction method. The structure and electrochemical performance of the as-prepared catalysts were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and linear sweep voltammetry (LSV). The performance of the as-prepared catalysts was compared with that of 40% (w) Co@Pt/C catalyst we synthesized previously. The sizes of Co@Pt(1:1) and Co@Pt(1:3) particles ranged from 2.2 to 2.3 nm, and the metal particles were well dispersed on the carbon support. The electrochemical specific area (ECSA) of 20% Co@Pt(1:1)/C (56 m²·g^-1) and 20% Co@Pt(1:3)/C (60 m²·g^-1) were higher than that of commercial 20% Pt/C (E-tek) (54 m²·g^-1). Compared with those of 40% Co@Pt(1:1)/C and 40% Co@Pt(1:3)/C, the half-wave potentials of 20% Co@Pt(1:1)/C and 20% Co@Pt(1:3)/C shifted to the positive direction, and they correspondingly showed improved catalytic performance. The low cost and high performance of the 20% Co@Pt/C catalyst make it a promising low-Pt catalyst for proton exchange membrane fuel cells.

Pyridine-doped, carbon-supported Co-phthalocyanine (Py-CoPc/C) nanoparticle catalysts were synthesized via a combined solvent-impregnation and milling procedure, using Co-phthalocyanine (CoPc) and pyridine (Py) as the catalyst precursors. The morphologies and compositions of the catalysts were characterized using X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and X-ray photoelectron spectroscopy (XPS). The electrocatalytic activities and stabilities were evaluated by linear sweep voltammetry (LSV), using a rotating disk electrode technique, in terms of their oxygen reduction reaction (ORR) activity as a function of Py doping. The results show that Py doping can significantly improve the catalytic activity of CoPc/C toward the ORR, and the optimal Py doping level is around 20% (i.e., 20%Py-20%CoPc/C), for which an onset potential of 0.20 V (vs SHE) and a half-wave potential of -0.03 V were achieved in 0.1 mol·L^-1 KOH electrolyte. Compared with 40%Py/C and the 40%CoPc/C catalyst, the half-wave potential on the 20%Py-20%CoPc/C catalyst for the ORR shifted positively by 160 mV and 15 mV, respectively. The number of electrons transferred for the ORR also increased from 1.96 to 2.38, indicating an enhancement in ORR selectivity. Scanning electron microscopy-EDX and XRD analysis revealed that the N mass fraction (w) and dispersion of CoPc on carbon are improved by Py doping, which improves adsorption of O₂ molecules on the catalyst surfaces. XPS analysis clearly showed pyridinic-N and graphitic-N in the Py-CoPc/C catalysts. Both are believed to be coordinated to Co ions on the catalyst surfaces, and this might be responsible for the enhanced ORR activity. An H₂/O₂ fuel cell using membrance electrode assembly (MEA), fabricated with a 20%Py-20%CoPc/ C cathode catalyst, generated a peak power density of 21 mW·cm^-1, which is 2.4 times that of CoPc/C under the same operating conditions.

The energy increasing rate (EIR) of a condensed droplet was analyzed during its growth in three different modes. The lowest EIR corresponding to one of the three ways was used as the criterion to determine the mode in which a condensed drop will increase its volume. The results show that the EIR according to the mode of increasing contact angle (CA) is much smaller than that according to the two other modes during the first period of growth of a condensate spot formed within a nanostructure. This means that the drop will grow, with CA increasing but the base area remaining constant, until a certain CA. After this, the EIR according to the mode of CA increasing becomes much higher than that according to the two other modes. The three-phase contact line of the drop starts to shift and the base area begins to increase while the CA remains constant. During this second period, the state of increased base area can be wetted; i.e., a Wenzel-state droplet forms with an apparent CA less than 160°. In contrast, the expanded base area can be in a composite state; i.e., a partially wetted droplet forms with a CA greater than 160° . The growth mode and its wetted state of a condensed droplet are strongly related to nanostructure. Partially wetted condensed drops can appear only on surfaces with nanopillars of a certain height and small pitch. The calculated results were consistent with experimental observations reported in the literature for the wetting states of condensed drops on nanotextured surfaces, with an accuracy of 91.9%, which is obviously higher than those calculated with reported formulas.

Spherical, flowerlike, and threadlike bismuth vanadates (BiVO₄) were synthesized via a controllable hydrothermal method without using any surfactant or template. The optical and photocatalytic properties of the BiVO₄ samples were investigated. The phase structures of the BiVO₄ samples were observed by X-ray diffraction (XRD), which indicated that the as-prepared samples possessed monoclinic cells. Transmission electron microscope (TEM) observations showed that BiVO₄ crystals with different morphologies were fabricated simply by manipulating the parameters of the hydrothermal reaction. On the basis of the structural analysis of samples obtained under different conditions, a possible mechanism for the formation of these distinct morphologies was proposed. UV-visible diffuse reflectance spectra (UV-Vis DRS) of the samples revealed that the band gaps of the BiVO₄ photocatalysts were about 2.19-2.33 eV. The as-prepared BiVO₄ photocatalysts exhibited higher photocatalytic activities toward the degradation of rhodamine B (RhB) under visible light irradiation (λ>420 nm) than commercial P25 TiO₂ and traditional N-doped TiO₂ (N-TiO₂). Spherical BiVO₄ showed the highest photocatalytic activity of the samples, decolorizing up to 100% of RhB upon visible light irradiation for 180 min. The reason for the different photocatalytic activities of the BiVO₄ samples fabricated at different pH was systematically studied by considering their structure and morphology.

The effects and mechanism of methyl viologen (MV²⁺) on photocatalytic hydrogen production over an active, stable catalyst sensitized by Eosin Y (EY) under visible light were studied by UV-Vis absorption, fluorescence spectroscopies and photoelectric experiments. The results showed that MV²⁺ increased the efficiency of electron transfer from excited states of EY to the surface of Pt/TiO₂ and suppressed accumulation of unstable intermediate EY^3-· by an oxidative and reductive quenching mechanism. MV²⁺ also improved the activity and stability of photocatalytic hydrogen production by an EY-sensitized Pt/TiO₂ system with triethanolamine (TEOA) as an electron donor. The effects of transient photocurrent and concentration of EY on the hydrogen production activity of dye-sensitized systems with and without MV²⁺ provided further evidence that MV²⁺ acted as an electron transfer agent to effectively improve photoinduced electron transfer and utilization efficiency.

In this paper, we studied the unfolding process of myoglobin (Mb) and its mutant Mb(D60K) induced by acid under macromolecular crowding conditions, using ultraviolet-visible absorption, synchronous fluorescence, and circular dichroism (CD) spectroscopies. The spectroscopic data showed that, with the addition of Dextran70 or Ficoll70, the denaturation midpoint of Mb(WT) decreased from 4.25 to 3.78 or 3.76, respectively. In addition, the acid tolerance of Mb(WT) improved under macromolecular crowding conditions. The denaturation midpoint of Mb(D60K) was 4.19, which was a slight decrease from that of Mb (4.25). Upon addition of Dextran70 or Ficoll70, the denaturation midpoint of Mb(D60K) decreased from 4.19 to 3.74 or 3.12, respectively. The spectroscopic results illustrated that the amino acid mutant and crowding agents could stabilize the microenvironment surrounding the heme and aromatic amino acid as well as the second structure of Mb, protecting its native state.

Pyruvate kinase M2 (PKM2) is well-known as a potential target for cancer therapy. In this study, the multicomplex-based pharmacophore (MCBP)-guided method was used to generate a comprehensive pharmacophore of PKM2 kinase based on a collection of crystal structures of PKM2- activator complex. This model was successfully used to identify the bioactive conformation and align 62 structurally diverse aryl-sulfamide derivatives. Quantitative structure-activity relationship (QSAR) analyses were performed on these PKM2 activators based on MCBP-guided alignment. With the comparative molecular field analysis (CoMFA) model, the cross-validated value (q²) was 0.545, and the non-crossvalidated value (r²) was 0.966. With the comparative molecular similarity indices analysis (CoMSIA) model, q² and r² were 0.653 and 0.987. These results may provide important information for further design of novel PKM2 activators.

The Na-Al-H complex hydride was prepared by reactive ball milling (NaH/Al+CeCl₃) and (NaH/Al+CeCl₃/yKH) (y=0.02, 0.04) composites under a hydrogen pressure of 3 MPa at room temperature, using NaH and Al powder as raw materials, as well as 2% (molar fraction) CeCl₃ and 2% CeCl₃/y% KH (y=0.02, 0.04) as dopant, respectively. The de-/hydrogenation properties show that the addition of KH can effectively improve the dehydrogenation kinetics of second decomposition step for Na-Al-H system. The (NaH/Al+CeCl₃/0.02KH) composite can complete dehydrogenation process within 20 min at 170℃, with od de-/hydrogenation cycling performance at relatively low temperature (100-140℃). Calculation by Kissenger method shows that the addition of KH could decrease the apparent activation energy of second decomposition step for Na-Al-H system, resulting in the decrease of desorption peak temperatures. Phase structure analysis shows that the enhanced second step dehydrogenation kinetics of Na-Al-H composite system is mainly ascribed to the lattice volume expansion of Na₃AlH₆ resulted from the addition of KH.

In this study, plate like Silicalite-1 samples with controlled thickness were synthesized using a SiO₂-TPAOH-H₂O-NH₄F (TPAOH: tetrapropylammonium hydroxide) system by careful tuning of the synthetic parameters. Samples were fully characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and thermogravimetry-differential thermal analysis (TG-DTA). We confirmed that the concentration of NH₄F and pH of the initial gel played important roles in controlling sample morphology. The morphologies of the samples changed from ellipse to plate like shapes as the molar ratio of NH₄F to SiO₂ was increased from 0 to 0.18. In addition, the thickness of the plates was controlled by regulating the amount of NH₄F in the gel. The thickness of the sample decreased as the amount of NH₄F increased, and reached its minimum when the NH₄F/SiO₂ molar ratio reached 0.4. Further increase of the molar ratio of NH₄F/SiO₂ increased the thickness of the plates because of their improved crystallinity. In these plate like particles, the b axis was perpendicular to the plate, as confirmed by HRTEM, which implies that these materials could show od accessibility for guest molecules because the b axis is the straight channel in MFI structures. All of the plate like Silicalite-1 samples were highly stable and their morphologies were retained even after treatment at 1100℃.

Mercapto acids can affect the obtaining CdTe quantum dots (QDs) with narrow size distribution and high fluorescent quantum yield (QY) that emit in the red to near-infrared region. To study their effects on CdTe QDs, three types of derivatives of 3-mercaptoisobutyric acid (MIBA) were designed and synthesized: hydrophilic side-chain derivative N-acetylcysteine (ACys), hydrophobic side-chain derivatives 3-mercapto-2-methylbutyric acid (MMBA) and 3-mercapto-2,2-dimethylpropanoic acid (MDMPA), and hydrophilic main-chain derivatives 3-mercaptoisobutoyl-3-aminopropanoic acid (MIBAPA), 3-mercaptoisobutoylglycine (MIBGly) and 3-mercaptoisobutoylaspartic acid (MIBAsp). To evaluate the effects of these MIBA derivatives on the properties of CdTe QDs, they were used as capping agents during hydrothermal synthesis of the QDs with sodium tellurite as the tellurium source. The effects of the mercapto acids were revealed by comparing the growth rate, and full width at half-maximum (FWHM) of the fluorescent peak of CdTe QDs capped with different mercapto acids. All three types of MIBA derivatives gave CdTe QDs with relatively narrow FWHM, similar to MIBA. The hydrophilic MIBA derivatives (ACys, MIBGly, MIBAPA, and MIBAsp) produced CdTe QDs with longer emission wavelength than those from hydrophobic derivatives. Hydrophilic side-chain MIBA, derivative ACys gave CdTe QDs with stronger fluorescence.

Au/Cu₂O heterogeneous spheres (HGS) were prepared by in situ reduction of preadsorbed AuCl₄^- on the surface of Cu₂O mesoporous spheres (MPS) linked by L-cysteine. The resulting products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (DRS), and N₂ physical adsorption. The photocatalytic activity of the samples was evaluated by photocatalytic degradation of methylene blue (MB) under visible light (λ>400 nm) irradiation. The experimental results revealed that the Cu₂O MPS kept their mesoporous structure after loading with Au, and small Au nanoparticles (NPs) with a diameter of ~4 nm were identified on the surface of the MPSs. N₂ physical adsorption analysis showed that the pore size distributions of Cu₂O MPSs were unchanged after loading with Au NPs. Using ethanol as a solvent retarded the redox reaction between AuCl₄^- and Cu₂O, avoiding damage to the mesoporous structures. The Au/Cu₂O HGSs exhibited higher visible-light photocatalytic activity for the degradation of methylene blue than the pure Cu₂O MPSs. The enhanced photocatalytic efficiency of the Au/Cu₂O HGSs was attributed to rapid charge transfer from Cu₂O to the loaded Au NPs as well as the surface plasmon resonance of Au NPs.

In(NO₃)₃/polyvinyl pyrrolidone (PVP) nanofiber precursors were synthesized using a traditional electrospinning method, and were then annealed at 500, 600, and 700℃ to form In₂O₃ nanofibers. The as-prepared In₂O₃ nanofibers were characterized using X-ray diffraction (XRD), thermal gravimetry and differential thermal analysis (TG/DTA), and field-emission scanning electron microscopy (FE-SEM). The results show that the In₂O₃ nanofibers crystallize well, with a small average grain size (about 24 nm) and a od mesoporous structure, when annealed at 500℃. The In₂O₃ nanofibers annealed at the three temperatures were further used to fabricate gas sensors. The test results show that the sensor based on In₂O₃ annealed at 500℃ has the highest response (about 7) to 10×10^-6 (volume fraction, φ) formaldehyde (HCHO) at an operating temperature of 240℃. CdO nanoparticles were also prepared using the same method; XRD and FE-SEM show that the average grain size of CdO is about 68 nm. Finally, the as-prepared In₂O₃ nanofibers were mixed with the as-prepared CdO in molar ratios of 1:1, 10:1, and 20:1, and the mixtures were used to fabricate gas sensors. The HCHO-sensing properties of the sensors based on pure In₂O₃ and In₂O₃/CdO composites with different molar ratios were investigated at each optimum temperature. The results show that the In₂O₃/CdO composite with a molar ratio of 10:1 has excellent sensing properties: the response to 10×10^-6 HCHO is 13.6, the response/recovery time is 140 s/32 s, and the selectivity is better at a lower operating temperature of 200 °C. In addition, the HCHO-sensing mechanism of the sensors based on the In₂O₃/CdO composites was briefly analyzed.