To evaluate the thermal safety of 2,2,2-trinitroethyl-N-nitromethyl amine (TNMA), basic data, including specific heat capacity (C_p) and thermal conductivity (λ), were estimated using empirical formulae. The standard enthalpy of formation of TNMA, Δ_fH_m^θ(TNMA, s, 298.15 K), was calculated by an additive method of contributing bond energy to heat of formation Q_f, and the standard combustion enthalpy Δ_cH_m^θ(TNMA, s, 298.15 K) and standard combustion energy ΔU_m^θ (TNMA, s, 298.15 K) and standard combustion energy ΔU_m^θ (TNMA, s, 298.15 K) were calculated by thermodynamic formulae. The detonation velocity, detonation pressure, and heat of detonation were estimated using the Kamlet-Jacobs equation. The heat of decomposition reaction (Q_d) of TNMA was estimated by an empirical formula, and the thermal behavior of TNMA was studied by differential scanning calorimetry (DSC). The kinetic parameters of the exothermic decomposition reaction of TNMA were obtained from analysis of DSC curves and standard volume of gas evolved (VH) vs time (t) curves determined using a highly sensitive Bourdon glass membrane manometer. The parameters used to evaluate the thermal safety of TNMA, such as the self-accelerating decomposition temperature (T_SADT), critical temperature of thermal explosion (T_be and T_bp), adiabatic time-to-explosion (t_TIad), 50% drop height (H₅₀) of impact sensitivity, critical temperature of hot-spot initiation (T_cr), thermal sensitivity probability density function S(T) for infinite plate-like, infinite cylindrical and spheroidal TNMAwith half-thickness and radius of 1 m at 300 K, peak temperature corresponding to the maximum value of the S(T) vs T curve (T_S(T)max), safety degree (SD), critical thermal explosion ambient temperature (T_acr), and thermal explosion probability (P_TE), were obtained by the above-mentioned basic data. Results show that (1) TNMA has better thermal safety and heat-resistent ability; but in comparison with cyclotrimethylenetrinitramine (RDX), the transition from thermal decomposition to thermal explosion of TNMA is easy to take place. (2) The thermal safety of large scale TNMA with different shape decreases in the order: sphere>infinite cylinder>infinite plate. (3) TNMA has high standard combustion energy and high chemical energy (heat) of detonation, and explosion performance level approaching that of HMX. It is sensitive to shock, has impact sensitivity level approaching those of pentaerythritol tetranitrate (PETN) and tetryl and can be used as a main ingredient of composite explosive.

Graphene hydrogels were prepared by the sol-gel method, and then used to prepare ammonium perchlorate (AP)/graphene composites by the incorporation of AP. The composites were dried naturally in air, freeze-dried, or dried with supercritical CO₂. Scanning electron microscopy (SEM), elemental analyses (EA), and X-ray diffraction (XRD) were used to characterize the structure of the AP/graphene composites dried using different methods. Furthermore, the thermal decomposition behavior of the AP/graphene composites was investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis/infrared spectroscopy (TG-FTIR). Drying method had an obvious influence on the morphology of the AP/graphene composites; only the AP/graphene composites dried with supercritical CO₂ showed similar three-dimensional networks and porous structure to graphene aerogels. Elemental analyses revealed that the AP contents in the AP/graphene composites prepared by drying naturally, freeze-drying, and supercritical CO₂ drying were 89.97%, 92.41%, and 94.40%, respectively. XRD results showed that AP was dispersed homogeneously on the nanoscale in the AP/graphene composites dried with supercritical CO₂ and the average particle diameter of AP was about 69 nm. DSC and TG-FTIR analyses indicated that graphene could promote the thermal decomposition of AP, particularly for the sample dried with supercritical CO₂. Independent of drying method, the low-temperature decomposition of the as-prepared AP/graphene composites was not observed and the high-temperature decomposition was accelerated. Compared to the other two drying methods, graphene in the AP/graphene composites dried with supercritical CO₂ showed most obvious promoting effects. The high-temperature decomposition temperature of the AP/graphene composites dried with supercritical CO₂ decreased by 83.7 ℃ compared with that of pure AP, and the total heat release reached 2110 J·g^-1. Moreover, graphene also took part in the oxidation reactions with oxidizing products, which was confirmed by the generation of CO₂.

The composite double base (DB)/hexogen (RDX)-modified double base (CMDB) propellants (Nos. DB001 and CMDB100) were prepared with the lead complex of 3,6-bis(1H-1,2,3,4-tetrazol-5-ylamino)-1,2,4,5-tetrazine (LCBTATz), with and without the ballistic modifier. Their thermal behaviors and nonisothermal decomposition reaction kinetics were investigated by thermogravimetry, derivative thermogravimetry (TG-DTG), and differential scanning calorimetry (DSC). For the LCBTATz-DB propellant, there was one mass loss stage in the TG curve and one exothermic peak in the DSC curve over the temperature range 350-540 K. For LCBTATz-CMDB, there were two continuous exothermic stages in the TG curve, and only one corresponding exothermic peak in the DSC curve over the range 390-540 K. The exothermal decomposition reaction mechanisms of LCBTATz-DB and LCBTATz-CMDB follow the functions f(α)=α^-1/2 and f(α)=2(1-α)^3/2, respectively (α: conversion degree). The self-accelerating decomposition temperatures (T_SADT), thermal ignition temperatures (T_TITT), critical temperatures of thermal explosion (T_b), adiabatic timesto-explosion (t_Tlad), and thermodynamic parameters of activation reaction were calculated, and the thermal safety was evaluated. For DB001, T_SADT=444.50 K, T_TITT=453.96 K, T_b=471.84 K; t_Tlad=39.36 s. For CMDB100, T_SADT=442.38 K, T_TITT=452.89 K,T_b=464.13 K,t_Tlad=21.3 s. As a high-efficiency combustion catalyst, LCBTATz in double-base propellants increases the propulsion rate and reduces the pressure index for larger scale pressures. This makes the DB propellant appear to have a significant super burning effect at 2-8 MPa and a "mesa effect" at 8-12 MPa. Meanwhile, the pressure exponent of the CMDB propellant decreased to 0.18.

2,2-Azobisisobutyronitrile (AIBN) is a typical material that shows overlap between endothermic phase change and exothermic decomposition. This phenomenon went against the kinetics of AIBN. To properly analyze the effect of endothermic phase change on the exothermic decomposition process and determine the non-isothermal behavior of AIBN in a solvent, a solution of AIBN (22.18% mass fraction) in aniline was tested under dynamic conditions by differential scanning calorimeter (DSC). Depending on heating rates, the onset temperature range of AIBN in aniline was from 79.90 to 94.47 ℃, and the decomposition enthalpy was 291 J·g^-1 greater than that in its pure state, which could be regarded as phase change enthalpy. Based on the Kissinger method, the differences of the activation energy E and the frequency factor A of AIBN and its solution were quite small. The thermal decomposition processes of AIBN and its solution were analyzed by the Friedman method, which showed that the reaction progress range was less than 0.20, in which the endothermic phase change of solid AIBN would disturb its exothermic decomposition. When α was greater than 0.20, the dependence of E(α) and ln(A(α)·f(α)) on α were roughly the same. These results show that aniline is an inertial solvent; that is, decomposition of AIBN is not disturbed by aniline. This means that the decomposition mechanism of AIBN in aniline could be regarded as the same as that in its solid state. The decomposition kinetics of AIBN could be described according to the Mampel power law, G(α)=α^3/2, which is based on the Friedman and Coats-Redfern integral methods, and the average apparent activation energy was 139.93 kJ·mol^-1.

The thermokinetics of the formation reactions of metal (Li, Na, Pb, Cu) salts of 3-nitro-1,2,4-triazol- 5-one (NTO) was studied using a microcalorimeter. On the basis of experimental and calculated results, three thermodynamic parameters (activation energy, pre-exponential constant, and reaction order), rate constant, three thermokinetic parameters (activation enthalpy, activation entropy, and activation free energy) and the enthalpies of the reactions to prepare the metal salts of NTO in the temperature range of 25-40℃ were obtained. The title reactions occur easily in the studied temperature range. Based on Hess' law, the values of Δ_fH_m⁰ (Li(NTO)·2H₂O, aq, 298.15 K) and Δ_fH_m⁰ (Na(NTO)·2H₂O, aq, 298.15 K) are obtained.

In this study, the conductivity of 13 ionic liquids (ILs) and 25 related binary mixtures were determined at temperatures ranging from 293.15-323.15 K. The conductivity data of the pure ILs and their mixtures were fitted using the Vogel-Tammann-Fulcher (VTF) equation. The ionic association in the ILs and IL mixtures was discussed using the parameters of the VTF equation. It was demonstrated that at the same temperature, the ILs with short side chain cations, low charge density anions, and weak hydrogen bonding force between cations and anions usually exhibited high conductivity. Anions had a more obvious effect on conductivity than cations. The ionic association in the mixtures was affected not only by the species but also by the composition of the mixture.

The dilution enthalpies of four crown ethers, namely 12-crown-4, 15-crown-5, 18-crown-6, and 4,13-diaza-18-crown-6, in pure water and mixtures of N,N-dimethylformamide (DMF) and water of various mass fraction (w=0-0.3) were determined at 298.15 K by isothermal titration microcalorimetry. The corresponding enthalpic pairwise interaction coefficients (h_xx) were evaluated according to the McMillan-Mayer theory. Values of h_xx were all positive and large, which indicates that hydrophobic components predominate in crown-crown self-interactions. There are two main kinds of mechanisms: (1) When hydrophobic-hydrophobic interactions occur, cosphere overlapping reduces the formation of water structure, which makes a positive contribution to h_xx. (2) Hydrophobic-hydrophilic interactions increasingly destroy the water structure because of cosphere overlapping, which also makes a positive contribution to h_xx. In addition, h_xx values of the four crown ethers follow the order: h_xx(18-crown-6)>h_xx(4,13-diaza-18-crown-6)≈ h_xx(15-crown-5) >h_xx(12-crown-4), which indicates that the larger the size of the crown ether ring, the stronger the hydrophobic-hydrophobic interaction; namely, that crown ethers are subject to macrocyclic hydrophobic effects.

A complex of a rare-earth metal (Ho) nitrate with glycine (C₂H₅O₂N), Ho(NO₃)₃(C₂H₅O₂N)₄·H₂O, was synthesized, and characterized by chemical analysis, elemental analysis, and infrared (IR) spectroscopy. The thermodynamic properties of the complex were also studied. The low-temperature molar heat capacities at constant pressure (C_p,m) of the complex were measured using a high-precision automatic adiabatic calorimeter over the temperature range from80 to 390 K. The experimental molar heat capacities at constant pressure were used to deduce the polynomial equations for the heat capacity as a function of reduced temperature by applying the least-squares method to the two smooth stages of the curve. Based on the thermodynamic relationships among heat capacity, entropy, and enthalpy, the thermodynamic functions (H_T,m-H_298.15,m) and (S_T,m-S_298.15,m) were derived from the heat capacity data, with temperature intervals of 5 K. The molar enthalpy and entropy changes of the transition process at about 350 K (Δ_trsH_m and Δ_trsS_m) were calculated from the heat capacity curve. The thermal stability of the complex was determined using differential scanning calorimetry (DSC).

Low temperature heat capacities of the compound Zn(Met)₃(NO₃)₂·H₂O(s) have been measured by a precision automated adiabatic calorimeter over the temperature range 78-371 K. The initial dehydration temperature of the coordination compound was determined to be T_D=325.10 K by analysis of the heat-capacity curve. The experimental values of the molar heat capacities in the temperature region have been fitted to a polynomial equation of heat capacities with the reduced temperature (X), [X=f(T)], by the least squares method. Smoothed heat capacities and thermodynamic functions relative to the standard reference temperature 298.15 K of the compound are derived from the fitted polynomial equation and listed at 5 K internals. Using 100 mL of 2 mol·L^-1 HCl(aq) as calorimetric solvent, with an isoperibol solution-reaction calorimeter, the standard molar enthalpy of formation of the compound was determined to be Δ_fH_m⁰[Zn(Met)₃(NO₃)₂×H₂O(s), s]=-(1472.65±0.76) J·mol^-1 by a designed thermochemical cycle.

Nucleobases in DNA and RNA are important building blocks of the genetic codes and are critical in transferring genetic information. In general, nucleobases have many tautomers; but in DNA and RNA molecules they are mainly presented in the most stable forms. Uncommon tautomers can cause mispairing of base pairs to form irregular structures of DNA and RNA that lead to spontaneous mutations during replication. Thus, systematic studies of nucleobase tautomers are very important in understanding the structures and the characteristics of DNA and RNA. This review summarizes the experimental and theoretical studies in the literature and our density functional calculations on all the nucleobase tautomers. The relative energies of nucleobase tautomers and the structures of their lowest-energy tautomers fromour calculations are in od agreement with the experimental values in the literature. In addition, we also summarize the information of electron affinities, ionization potentials, and proton affinities of nucleobases reported in the literature.

A critical thermodynamic optimization of the Al-Fe-P ternary system was performed using the CALPHAD method. Among the sub-binary systems in the Al-Fe-P system, the Al-P systemwas reassessed according to its related experimental information. The thermodynamic descriptions of the Al-Fe and Fe-Pbinary systems were taken from previous studies with minor modifications. The parameters of the thermodynamic model of the Al-Fe-P ternary systemwere optimized based on available experimental phase diagramdata and thermodynamic properties. One set of consistent parameters of the Gibbs energies of all phases, which can satisfactorily reproduce most of the experimental phase diagramdata, was obtained. By employing the driving force criterion with the present thermodynamic description, the experimentally reported composition dependence of the glass-forming ability of the Al-Fe-P systemcould be explained thermodynamically.

The density, viscosity, and conductivity of protic ionic liquid (PIL) N,N-dimethylethanolammonium propionate (DMEOAP) were determined in the temperature range of 283.15-333.15 K. The influence of temperature on density, viscosity, and conductivity is discussed. The thermal expansion coefficient, molecular volume, standard molar entropy, and lattice energy of DMEOAP were calculated using empirical and semiempirical equations. The molar conductivity of DMEOAP was determined fromdensity and conductivity data. The temperature dependence of viscosity and conductivity data was fitted using the Vogel-Fulcher-Tammann (VFT) equation. The relationship between molar conductivity and viscosity was determined by the Walden rule.

A 1,10-phenanthroline dipyrido[3,2-a:2',3'-c]-7-aza-phenazine derivative (dpapz) and its Cu(I) complex [Cu(dpapz)₂]PF₆ are prepared and characterized by proton nuclear magnetic resonance spectroscopy (¹H NMR), Fourier transform infrared spectroscopy (FTIR), and high resolution electrospray ionization mass spectrometry (HR ESI-MS). The interactions of dpapz and [Cu(dpapz)₂]PF₆ with calf thymus DNA (CT DNA) are studied by ultraviolet-visible spectroscopy (UV-Vis), fluorescence spectroscopy, DNA melting temperature, and cyclic voltammetry. When the ligand dpapz interacts with DNA, there is no red shift of the absorption peak and only a small hypochromic (<30%) effect on the absorption spectra. In addition, the interaction leads to a slight increase in the melting temperature of DNA (ΔT_m=7.8 ℃). All the results indicate that groove binding is the primary interaction of dpapz with CT DNA. However, when [Cu(dpapz)₂]PF₆ interacts with DNA, there is a red shift of the absorption peak (2-3 nm), a large hypochromic effect on the absorption spectrum (>50%), and a significant increase in the melting temperature of DNA (ΔT_m=11.1 ℃), indicating that [Cu(dpapz)₂]PF₆ electrostatically associates with DNA in a partial intercalation manner. The complexes of dpapz and [Cu(dpapz)₂]PF₆ with DNA are further confirmed by ethidium bromide (EB) fluorescence assays and cyclic voltammetry. The association constants for dpapz and [Cu(dpapz)₂]PF₆ with CT DNA are 2.88×10⁵ and 5.32×10⁵ mol·L^-1, respectively. The yield of singlet oxygen produced by [Cu(dpapz)₂]PF₆ is similar to that of dpapz, while the yield of superoxide anion radical for [Cu(dpapz)₂]PF₆ is lower than that of dpapz. Active oxygen quencher experiments indicate that singlet oxygen, superoxide anion radicals, and hydrogen radicals all take part in the photocleavage of DNA by [Cu(dpapz)₂]PF₆ and dpapz. However, [Cu(dpapz)₂]PF₆ causes more photodamage of plasmid DNA than does dpapz, most likely because of its higher affinity for DNA.

To find out what interaction dictates the molecular stability is essential, yet still controversial even for simplest molecules. Here, using water cluster as an example, we employ quantum molecular dynamics to generate a total of 185 conformations for octamer water clusters and then employ two energy partition schemes from density functional theory to pinpoint the principles verning their stability. We found that their stability is strongly correlated with steric repulsion and exchange-correlation interactions. Explanations using two different quantities are also proposed (with the correlation coefficient larger than 0.99). This work sheds light to the fundamental understanding towards the origin and nature of molecular conformational stability for water clusters and other molecular complexes formed through intermolecular interactions.

Car-Parrinello molecular dynamics simulations are performed on Be²⁺ ion in water, methanol, and ethanol to study their structural properties and then compared with experimental and theoretical data. Excellent agreement is obtained with existing experimental data for the structure of the first solvation shell around the Be²⁺ ion. Radial distribution functions, coordination number, and angular distributions are used to examine the solvation structure in the first solvation shell of Be²⁺. Be²⁺ has a very well-defined first solvation shell of four solvent molecules with a tetrahedral symmetry. The solvation shells of Be²⁺ in water, methanol and ethanol have well-defined, long-lived tetrahedral structures. Exchange of solvent molecules between the first and second solvation shells is not observed. Spatial distribution function (SDF) results show that the maximum of the Be²⁺ distribution lies along the same direction as that of acceptor of hydrogen-bonded solvent molecules.

Density functional theory M06-2X/6-31G(d, p) was used on complexes of calix[4]pyrrole (CP) with halide anions (X^-=F^-, Cl^-, Br^-) and NH₄⁺-X^- ion-pairs. Geometries, binding energies, natural bond orbital analysis, and multifunctional wave function analysis (Multiwfn) were presented in detail. The results indicated that the interaction between the calix[4]pyrrole and halide anions mainly involved hydrogen (H)-bonds. Long-range van der Waals forces and steric effects were determined in the CP-Cl^- and CP-Br^- systems by Multiwfn analysis. Calix[4]pyrrole forms stable complexes with NH₄⁺-X^- ion-pairs mainly through H-bonds and electrostatic interactions, as well as via cation-π interactions. The 2:1 complexes of CP and anions or ion-pairs were also considered theoretically, but 2:1 is not the dominant stoichiometry relative to the 1:1 complexes. The current study also demonstrates that calix[4]pyrrole functions not only as an anion receptor, but also as a od ion-pair receptor, especially in cases involving fluoride ions.

Density functional theory (DFT) and self-consistent periodic calculations were used to investigate the adsorption of formic acid (HCOOH) and carbon monoxide (CO) at eight sites, such as top, bridge, hcp and fcc, on a Pt-Sn(111)/C surface. The vibrational frequency, electric charge, energy band and density of states of HCOOH before and after adsorption on a Pt-Sn(111)/C surface were determined. The results show that before doping, the favored adsorption site for HCOOH and CO is the fcc-Pt3 site. After doping the surface with Sn, the Fermi level moves to the right, the conduction band broadens, and the valence and conduction bands lower slightly. The change of the electronic structure on Pt-Sn(111)/C promotes both the adsorption and dissociation of HCOOH, which can improve the performance of anode catalysts for direct formic acid fuel cells (DFAFCs). Based on the anti-poisoning analysis of the catalyst surface, it was also found that the adsorption energy of CO on Pt-Sn(111)/C surfaces is lower than that on Pt(111)/C ones. The results show that the adsorption energy of CO on Pt-Sn(111)/C decreases through two ways, and the anti-poisoning ability of the catalyst towards COis improved after doping with Sn.

The adsorption equilibriumproperties of H₂ molecules in various metal-organic frameworks (MOFs) including IRMOF-61, IRMOF-62, and IRMOF-1 were studied using the grand canonical Monte Carlo (GCMC) simulation method with the optimized parameters obtained using the DREIDING force field. The calculated parameters could exactly reproduce the adsorption isotherms of H₂ molecules in IRMOF-62. However, they may underestimate the adsorption isothermof H₂ molecules in IRMOF-61 at lowpressure. The H₂ storage capacities of IRMOF-61 and IRMOF-62 with interpenetrating frameworks were not significantly higher than that of IRMOF-1 at roomtemperature. H₂ molecules were preferentially adsorbed near Zn₄O units, which were located close to the benzene rings, according to the probability density distribution of H₂ molecules in the above MOFs under adsorption equilibriumconditions at 77 K, 100 kPa, and 3.0 MPa. For the MOFs with interpenetrating frameworks, the area with preferential adsorption sites for H₂ molecules is smaller and more scattered than the MOF without because of their smaller cavity sizes. The organic linker should be of appropriate length to promote the formation of an interpenetrating framework, which can enhance the interaction between the framework and H₂ molecules, and thus improve H₂ storage capacity. If the organic linker is too long, it will decrease the adsorption capacity of the MOF for H₂ because more corners unable to adsorb H₂ are formed.

The geometrical structures of a series of neutral, protonated, and deprotonated aromatic amino acids (Phe, [Phe―H]^-, PheH⁺, Tyr, [Tyr―H]^-, TyrH⁺, Trp, [Trp―H]^-, and TrpH⁺) were optimized using density functional theory (DFT)-B3LYP with a 6-31G^* basis set. Based on the optimized structures, the excited state properties were studied using time-dependent DFT at the B3LYP/6-31G^* level. We calculated the second-order polarizabilities for second harmonic generation with the sum-over-states method. We examined the origins of the nonlinear optical responses and determined the cause for the variation in the second-order polarizabilities. Our calculations show that the second-order polarizabilities for protonated, and deprotonated aromatic amino acids are much higher than those for the neutral aromatic amino acids, with the order Phe < PheH⁺ < [Phe―H]^- and Tyr < TyrH⁺ < [Tyr―H]^-. By analyzing their electronic origins, we find that charge transitions in the side chains (benzene, phenol, and indole) make the main contributions to the second-order polarizability for neutral aromatic amino acids. For protonated and deprotonated aromatic amino acids, π→π^* charge transfers within indole rings, and charge transfers within amino groups and the carboxyl groups attached to alpha-carbon atoms make almost identical contributions to the second-order polarizability.

The inhibition effect of two pyrimidine derivatives, 2- hydroxypyrimidine (HP) and 2- mercaptopyrimidine (MP), on the corrosion of cold rolled steel (CRS) in 1.0-5.0 mol·L^-1 HCl is investigated by mass loss, potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), and quantum chemical calculations. The results show that HP and MP are both od inhibitors of corrosion of CRS in 1.0 mol·L^-1 HCl solution. The adsorption of these inhibitors onto the CRS surface obeys the Langmuir adsorption isotherm. Inhibition efficiency increases with inhibitor concentration, and decreases with hydrochloric acid concentration. The thermodynamic parameters of adsorption (adsorption equilibrium constant (K) and adsorption free energy (ΔG⁰)) and kinetic parameters of corrosion (apparent activation energy (E_a), pre-exponential factor (A), corrosion rate constant (k), and kinetic reaction constant (B)) are also calculated. Based on these parameters, the mechanism of inhibition is discussed. Potentiodynamic polarization curves show that HP and MP act as mixed-type inhibitors. EIS exhibit one capacitive loop, and the charge transfer resistance increases with inhibitor concentration. The results of quantum chemical calculations indicate that MP exhibits higher adsorptive ability than HP, which is in od agreement with the experimental data.

Based on hydrogen titanate nanotubes prepared by a low-temperature hydrothermal technique, Cu-doped titania nanotube (Cu-TNT) catalysts were prepared using absorption-calcination methods. They were characterized by X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (UV-Vis-DRS), and electrochemical techniques. Density functional theory (DFT) was used to calculate the nanotube band structure and density of states. Cu/Ti atomic ratios in the synthesized powders were very close to the nominal values, and the Cu-doped TiO₂ lattice exhibited improved visible-light absorption. This was because the valence band, formed by hybridization of O 2p states with Cu 3d states, was negatively shifted. Thus, the band gap was reduced to 2.50-2.91 eV and the samples exhibited visible-light responses. Toluene was chosen as a model pollutant to evaluate the removal capacity and the CO₂ mineralization rate of volatile organic compounds under visible light. Pure TNT displayed poor visible-light activity, and the activities of samples with >0.1% Cu doping were also weak. Samples doped with 0.1% Cu exhibited optimumvisible-light photocatalytic oxidation activity, with a 77%toluene degradation efficiency and a 59%mineralization rate in 7 h.

Aseries of Fe₃O₄-modified Pt-Ru/C nanocomposite catalysts were prepared by impregnation and hydrazine hydrate reduction of Pt and Ru precursors. Various Pt/Ru mass ratios of the catalysts were examined in terms of catalytic activity. They were characterized by transmission electron microscopic measurements (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The average diameters of the catalysts with different mass ratios of Pt/Ru were in a range of 2.2-2.5 nmwith narrowsize distributions. The valence states of the nanoparticles indicate strong interactions between the Pt and the carbon support or with Fe₃O₄. The XRDpatterns of the 8Pt-1Ru/Fe₃O₄/C, 6Pt-1Ru/Fe₃O₄/ C, 4Pt-1Ru/Fe₃O₄/C, and 2Pt-1Ru/Fe₃O₄/Ccatalysts have similar profiles, which are attributed to the cubic phase of pure Fe₃O₄ (i.e., no Pt or Ru present). These catalysts selectively hydrogenate ortho-chloronitrobenzene (o-CNB) to the corresponding ortho-chloroaniline (o-CAN) under solvent-free conditions that not only allowed high substrate concentrations promoting the hydrogenation reaction, but also enabled easy product separation and purification. They exhibited excellent catalytic activity (turnover frequency (TOF) range: 0.98-2.09 mol·mol^-1·s^-1) and up to 100% o-CAN selectivity, which was composition-dependent. The o-CAN yield selectivity monotonically increased with the proportion of Ru; however, the catalytic activity decreased. The high catalytic activity and selectivity of Pt-Ru/Fe₃O₄/Cnanoparticles are attributed to electron transfer between the two metals and Fe₃O₄.

Two types of aerogel silica, denoted as SiO₂-A(or B)G are synthesized with either solvent substitution (A) or solvent substitution-surface modification (B) under atmospheric conditions. Aerogel silicasupported Ni catalysts are then prepared via impregnated (IM) and polyvinylpyrrolidone (PVP)-added IM methods, and their performances for the partial oxidation of methane (POM) are investigated. The similar initial catalytic performances (activity and selectivity) are observed over the different Ni/SiO₂ catalysts. With respect to POMstability, Ni/SiO₂-BG is significantly worse than Ni/SiO₂-AG, while catalysts with PVP addition (during preparation) exhibit a significant improvement. In this case, Ni/SiO₂-BG-PVPis comparable to Ni/SiO₂-AG-PVP. We characterize the catalysts with X-ray diffraction (XRD), temperature-programmed hydrogen reduction (H₂-TPR), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) analysis. We find that there are hydroxyls on the SiO₂-AG surface that favor their interaction with hydrophilic metal species, while on the SiO₂-BGsurface there are organic groups that do not interact with hydrophilic metal species. In addition, with the help of PVP, metal species can access the deep pores of hydrophilic/hydrophobic silica gels. Then, the contraction of the silica framework and the growth of metal particles are inhibited during calcinations, enhancing interactions between Ni and the silica gels. These (benefits fromsurface hydroxyls and PVP) result in significant improvements in the catalysts with respect to POMstability.

Zr_0.5Ti_0.5O₂ was prepared by co-precipitation and tested for its catalytic performance under supercritical conditions when mixed with a CeO₂-Al₂O₃ (CA) base catalyst. The catalysts were characterized with an automatic adsorption instrument (BET method), X-ray diffraction (XRD), transmission electron microscopy (TEM), and temperature programmed desorption (TPD). It was found that Zr_0.5Ti_0.5O₂ significantly lowered the temperature of the cracking reaction, and increased the thermal cracking gas rate by a factor of 2.8 times as large as that at 600 ℃ for the CAbase catalyst. The gas rate was increased by a factor of 4.0 times when it was doped into the CAbase catalyst, and the heat sink increased by 0.55 MJ·kg^-1 over that of thermal cracking at 650 ℃. BET results show that the Zr_0.5Ti_0.5O₂-doped CAbase catalyst has a double-pore structure that enhances ethylene selectivity. NH3-TPD result indicates that the acidity of the catalyst increased by 4.0 times, indicating improved surface acidity conducive to alkene generation.

Asurfactant with long alkyl chains and glutamic acid, N^α-dodecyl-L-glutamic acid, was synthesized. Micelles of this surfactant were used to catalyze the hydrolysis of methyl-β-D-cellobioside (MCB), a model substrate of cellulose, under mild conditions. The results indicate that the functional micelle displayed effective catalytic activity for the hydrolysis of MCB to glucose at low temperature (90℃) and an optimal pH of 5.0. The first-order reaction rate constant (k_m) of MCB hydrolysis catalyzed by the synthesized micelles was calculated based on the phase separation model of micellar catalysis. The hydrolysis of MCB catalyzed by the cooperative systems of micelles with glutamic acid (Glu) or histidine (His) was also investigated. The addition of amino acids promoted the hydrolysis of MCB, and the maximumcatalytic efficiency was reached at a molar concentration ratio of micelles to amino acids of 1:1. Temperature considerably influenced the reaction rate and product of MCB hydrolysis. The yield of glucose from MCB hydrolysis catalyzed by the cooperative system of micelles with Glu reached more than 36.6%after 1.5 h at 130℃. The kinetics of this reaction was studied; the apparent first-order rate constants (k_obsd) were obtained and the activation energy (E_a) calculated for the formation of glucose was 97.18 kJ·mol^-1.

Dy³⁺-doped Ca₉La(PO₄)₇ phosphors were synthesized by a high-temperature solid-state reaction. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to determine the crystal structure and size of the prepared materials. Photoluminescence excitation and emission spectra of the Dy³⁺-doped Ca₉La(PO₄)₇:Dy³⁺ phosphors were measured. The samples exhibited a broad absorption band in the range of 300-460 nmand a series of individual absorption peaks of Dy³⁺. Blue (481 nm) and yellow (573 nm) emissions combined to generate the observable white-light emission of the Dy³⁺-doped Ca₉La(PO₄)₇:Dy³⁺ phosphors with suitable Commission Internationale de L'Eclairage (CIE) chromaticity coordinates around the colorless point (0.313, 0.329) when the phosphors were excited at 350 nm. Concentration quenching was clearly observed as the concentration of Dy³⁺ dopant was increased. The most intense emission corresponded to a optimummolar fraction of doped Dy³⁺ ions of 0.05. The mechanismof concentration quenching was dominated by electric dipole?dipole interactions.

Persistent organic pollutants (POPs) cause various diseases in both human and wildlife and have become a new global environmental problem. The toxic effects of POPs can be induced through their binding to specific proteins in the body. In the present work, a reverse virtual screening method based on molecular docking was used to search for potential protein targets for two POPs, 4,4'-dichlorodiphenyldichloroethane (4, 4'-DDD) and 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153), froma protein structure database. Targets ranked in the top 5%were chosen for analysis using experimental information. All known targets appeared in the top 5% of targets. This study not only increases understanding of the toxic mechanismof POPs, but may also aid the design of novel recognition elements in biosensors.

Using PEG4000-DL-aspartic acid as a composite soft template, Al(NO₃)₃ as an aluminumsource and urea as an alkali source, homogeneous rambutan-shaped AlOOH nanomaterials were successfully synthesized by a simple heating method under atmospheric conditions. The effects of the concentrations of reactants and additives on the morphology and size of the particles were studied and the possible formation mechanismof the γ-AlOOH nanostructures was explored. The rambutan-like γ-AlOOH particles had a core-shell structure resembling a ball within a ball. Based on the statistical results fromSEMimages of the particles, the ball diameter, external diameter, shell thickness and length of burr-like projections were about 400, 600, 15 and 60 nm, respectively. Results indicate that γ-Al₂O₃ retained the morphology of the AlOOH precursor following calcination at 600℃ for 5 h. Brunauer-Emmett-Teller (BET) N₂-adsorption experiments showed that the specific surface area of rambutan-shaped γ-Al₂O₃ reached as high as 299.97 m²·g^-1.