Catalysts of cobalt-cerium composite oxide doped with series of alkaline earth metals were prepared using the citrate method. Results of catalytic activity tests showed that the addition of alkaline earth metals enhanced the efficiency of N2O decomposition according to the following order: Mg<Ca<Sr,Ba. Characterization of these catalysts was done using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area measurement, X-ray photoelectron spectroscopy (XPS), oxygen temperature-programmed desorption (O2-TPD) and hydrogen temperature-programmed reduction (H2-TPR). Results indicated that the addition of alkaline earth metals did not change the crystal structures and specific surface areas of catalysts, but did enhance the electron donation ability of the active site (Co2+). The surface reaction of N2O with Co2+ involved electron donation from Co2+ to the anti-bonding orbital of N2O that resulted in the release of N2. The desorption of residual oxygen leads to the regeneration of the active site (Co2+) through the donation of electrons back to Co3+. We conclude that the addition of alkaline earth metals promotes surface reactions of N2O with Co2+ by facilitatingelectron donation from the active site. This process is the rate-determining step for purecobalt-cerium composite oxide catalysts and the catalytic activity for the decomposition of N2O is thus improved.

Apyrene-containing glucose derivative (PSDAPG) was synthesized and characterized. Its gelation behavior in 36 solvents was evaluated and the compound geled 16 of the solvents tested. Interestingly, PSDAPGwas a super gelator for 1-decanol and its lowest gelation concentration (LGC) was 7.0×10-4 g·mL-1. PSDAPG was found to behave as a “bifunctional gelator”as it gels in both water and organic solvents. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H NMR) spectroscopy and fluorescence spectroscopy reveal that the gelator adopts different supramolecular network structures in different solvents. Additionally, hydrophobic and π-π stacking interactions exist between the pyrene structures of the gelator molecules. Hydrogen bonding between the glucose residues also plays a crucial role in the spontaneous  formation of gel networks. Fluorescence emission spectra of PSDAPG in the solution state and in the gel state were characterized by monomer emission and excimer emission. Profiles of the two types of spectra were quite different. We found that the monomer emission increased and the excimer emission decreased as the gelation process proceeded. This  indicates that formation of gel networks greatly suppresses the mobility of pyrene units in the gelator and results in lower excimer formation efficiency via Birks' scheme.

Visual observations of tetrahydrofuran (THF) hydrate formation and dissociation processes with 5A-type zeolite powder were made at normal atmospheric conditions and below zero temperature by microscope. Results indicate that 5A-type zeolite powder can promote THF hydrate growth. At the same time, in the presence of 5A-type zeolite, agglomerated crystals and vein-like crystals of THF hydrate were also formed. 5A-type zeolite powder increases the crystallization temperature and decreases the dissociation temperature. The particle size distribution of 5A-type zeolite powder influences THF hydrate formation and its dissociation characteristics significantly.

We performed molecular dynamics (MD) simulations to investigate anionic surfactant sodium dodecyl benzene sulfonate (SDBS) adsorption onto a silica surface from solution. Various water phases of different thickness were constructed to investigate the difference between the solid/liquid and the air/liquid interface. We found that surfactant molecules adsorbed on silica surfaces within a short simulation time and they formed a surfactant layer via an interaction between the hydrophobic alkyl chain and the SiO2 surface. With an increase in water phase, one hemi-cylindrical micelle with a hydrophobic core formed on the SiO2 surface when a large amount of surfactant molecules adsorbed. The potential of mean force potential between the polar head of the surfactant and Na + ions or water molecules shows that the dissociation energy barrier is much larger than the combination energy barrier leading to more Na+ ions gathering around the polar head and fewer Na+ in solution. SDBS and water molecules can form complexes through H-bonding at the air/liquid or solid/liquid interface. Simulation results show that molecular dynamics can be used as an adjunct and can provide necessary information for microstructural property experiments.

We report on the formation of a molecule-ion adduct of β-cyclodextrin (β-CD) with sodium arsenite (SA) both in solid state and in aqueous solution. The adduct was characterized using Fourier transforminfrared spectroscopy, powder X-ray diffraction, differential thermogravimetric analysis, gas chromatography coupled to time-of-flight mass spectrometry, UV-Vis spectroscopy, 1H nuclear magnetic resonance titration and electrospray ionization mass spectroscopy. We found that a weak molecule-ion interaction was responsible for the difference in spectral properties in solid state and in aqueous solution as well as for the difference in thermal decomposition behavior between β-CD, SA and the adduct. The novelty and complexity of this interesting molecule-ion interaction was revealed by a redox reaction based on the data of gas chromatograph coupled to time-of-flight mass spectrometer and by the formation of the 1:1 (molar ratio) supramolecular ion complex, Na+-β-CD, based on its electrospray ionization mass spectrum.

The dispersion of highly concentrated multiwalled carbon nanotubes (MWNTs) in ethanol without polymer or covalent functionalization would generally facilitate the addition of MWNTs to a wide range of composite materials. To this end, suspensions of MWNTs in ethanol with various surfactants were prepared and their stabilities were evaluated. Non-ionic surfactants such as Triton X-100 and Tween 65 could suspend high-loading nanotubes in ethanol. MWNT suspensions in ethanol with Triton X-100 and Tween 65 initial supernatant concentrations of 1.0 g·L-1 were prepared and their concentrations were more than 0.50 and 0.35 g·L-1 after 240 h, respectively. These concentrations for MWNT suspensions, which are stable over the long term in ethanol without polymer or covalent functionalization, are higher than others reported in literature. The structural advantage of these non-ionic surfactant molecules for MWNT dispersion is discussed and a schematic representation is given to illustrate their adsorption on nanotube surfaces. The existence of surfactant molecules adsorbed on the nanotube surfaces was confirmed by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy(TEM).

The surface enrichment and phase separation structures of epoxy resin and poly(ε-caprolactone)-block-polydimethylsiloxane-block-poly(ε-caprolactone) triblock copolymer (PCL-b-PDMS-b-PCL) blends were studied using tapping mode atomic force microscopy (TM-AFM) and frictional force microscopy (FFM). Friction and wear properties show that the surface is enriched with the PDMS component and it reaches a stable state at a PCL-b-PDMS-b-PCL mass fraction of about 30%. Contact angle measurements on the surface also support these results.

A series of well-defined polydimethylsiloxane-b-poly(ethylene oxide) (PDMS-b-PEO)  amphiphilic diblock copolymers were synthesized by the combined use of anionic ring-opening polymerization of hexamethylcyclotrisioxane (D3) with n-butyllithium as the initiator and hydrosilation between Si—H terminated PDMS and ally terminated PEO homopolymers. The structures of PDMS and amphiphilic diblock copolymers PDMS-b-PEO were verified by nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy analyses. The diblock copolymers showed monomodal gel permeation chromatography (GPC) traces which indicated narrow molecular weight distributions (MWDs). Additionally, the solution properties of these diblock copolymers were investigated using tensiometry and transmission electron microscopy (TEM) . The equilibriumsurface tension γ and critical micelle concentration (cmc) of PDMS-b-PEO in an aqueous solution was also investigated. Interestingly, the cmc increases as the length of the hydrophobic chain increases. Transmission electron microscopy showed that PDMS-b-PEO diblock copolymers in the aqueous solution self-assembled into various morphologies including spheres, rods, and vesicle aggregates.

The T-jump/FTIR(Fourier transforminfrared) spectroscopy technique was used to study the flash pyrolysis of metallic (Li, Na, K, Mg) compounds of trinitrophloroglucinol (TNPG, 2,4,6-trinitro-1,3,5-trihydroxybenzene). Volatile metallic compounds liberated during the flash pyrolysis of trinitrophloroglucinol metallic (Li, Na, K, Mg) compounds were determined. A curve showing the concentration of gas with time during flash pyrolysis was also derived. A qualitative and quantitative analysis of the main IR-active gas products resulted from the thermal decomposition was carried out. The REAL program was used to study the components of the combustion products, reaction thermodynamics and the burning temperature of trinitrophloroglucinol metallic (Li, Na, K, Mg) compounds, which were compared with experimental results gained fromthe T-jump/FTIR spectroscopy technique.

A group of nano-TiO2 film catalysts with rutile/anatase mixed crystal structures were prepared by a magnetron sputtering method. The photodegradation of phenol was employed to evaluate the photocatalytic activities of the filmcatalysts.With less rutile content in the catalysts, photocatalytic activities improved gradually. Filmproperties were investigated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), surface photovoltage spectroscopy (SPS) and atomic force microscopy (AFM). Results indicate that all films have a rutile/anatase mixed crystal structure. With less rutile content the amount of hydroxyl groups (OH) and bridging oxygen atoms (—O—) on the surfaces of catalysts increase gradually and the Fermi levels gradually shift upwards as well. Surface species including hydroxyl groups and bridging oxygen atoms are advantageous for the photocatalytic reaction. Furthermore, because of the shifting of the Fermi level, the surface band bending of TiO2 at the interface of TiO2/H2O is enhanced leading to an increase in the charge carrier separation and an improvement in the photocatalytic activity.

We calculated the He atom ground-state energy using a double generalized Laguerre polynomial in the weakest bound electron potential model (WBEPM) theory. An expression for the expectation value of the He atom ground-state energy was derived.We obtained minimumvalues for the He atomground-state energy (Emin). A comparison was made to the results from the Hartree-Fock (HF) method using a double zeta function. Our result was slightly better than the result obtained using a double zeta function in the HF method. We thus show that the linear combination technique can easily be used in WBEPM theory.

Based on the atomic andmolecular reaction statics, the ground electronic states of XOn+ (X=Ru, Rh, Pd; n=0, 1) and their corresponding dissociation limits were systematically examined. Using the density functional B3P86 method in conjunction with the LANL2DZ basis set forXatoms and aug-cc-pVTZ basis set for Oatom, we investigated molecular equilibrium geometries and dissociation energies for these systems. Analytical potential energy functions of XOn+ (X=Ru, Rh, Pd; n=0, 1)were determined using theMurrell-Sorbie function. Spectroscopic data forXOn+ (X=Ru, Rh, Pd; n=0, 1) and the first vertical ionization potentials of the neutral XO(X=Ru, Rh, Pd) moleculeswere calculated aswell.

Undoped K2La2Ti3O10 and Fe3 + doped K2La2Ti3O10 samples were prepared by the sol-gel method and characterized by X-ray diffraction (XRD), UV-Vis diffuse reflectance spectra (DRS) and X-ray photoelectron spectroscopy (XPS). The effects of Fe3+ doping quantity on the properties and photocatalytic activity for hydrogen evolution were investigated. Results showed that Fe-doped K2La2Ti3O10 showed stronger absorption in the 400-650 nm range and this expanded to the visible light (λ>400 nm). Doping with Fe3+ raised the photocatalytic activity for hydrogen generation and the optimumamount of Fe3+ doping was found to be nFe/nTi=0.04. At this ratio and under visible light the rate of hydrogen evolution of Fe-K2La2Ti3O10 was 1.92 μmol·h-1 and this was 4 times higher than that of undoped K2La2Ti3O10 when 120 mL of reactive liquid (CH3OH(30 mL)+H2O(90 mL)) containing 0.1 g photocatalyst was used.

To increase the performance of TiO2 nanotube array electrodes in solar cells, we prepared self-organized TiO2 nanotube arrays on a titaniumsubstrate in 0.5% (w, mass fraction) NH4F/glycerol by anodic oxidization at a constant potential. The electrodes were then quenched in water at different temperatures. These quenched TiO2 nanotube array electrodes were then characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV). Experimental results indicated that the quenching process produced many surface defects and also resulted in fragmentation of the TiO2 nanotubes. We found that the sample quenched in water at 0 ℃ contained the more Ti3+ surface defects, OH groups and nanotube fragments. These properties improved its photoelectrochemical performance significantly. This sample resulted in 96.2% photodegradation rate of methyl orange after irradiation for 40 min.

Open system pyrolysis modeling of immature Huolinhe lignite (vitrinite reflectivity, ROmax of 0.33%) was carried out and an on-line curve for the methane generation rate was obtained using a thermogravimetric analyzer coupled to a quadrupole mass spectrometer (TG/MS). Five peaks were suitable for curve fitting. A kinetic analysis of these fitted curves indicated that the lowest temperature peak represented desorption of adsorbed methane in coal and the four other peaks were from pyrolytic methane generation. These results indicated four types of reactions as determined by kinetic analysis combined with the structural characterization of coal by 13C-NMR and quantum chemical calculations. From the order of peak fitting, the first type of reaction involves a cleavage of the aliphatic carbons linked to O atoms; the second includes two reactions, a β-secession of short chain aliphatic functional groups and a secondary cracking of long chain aliphatic hydrocarbons that were formed during the primary pyrolysis of coal; the third is a demethylation of methyl-linked aromatic clusters; and the fourth is an aromatization of aliphatic substances within the coal structure and subsequent condensation.

Glutathionyl ferrocene (GSH-Fc) was synthesized from glutathione and ferrocenyl amine using O-(benzotriazol-yl)-N,N,N',N'-tetramethyluronium(HBTU)/1-hydroxybenzotrizole (HOBT) as coupling agents in solution with a yield of 23.2%. The compound was characterized by 1H-NMR, IR and MS. Interactions of bovine serum albumin (BSA) with glutathionyl ferrocene were investigated by electrochemical methods. Experimental results revealed that there were specific interactions between BSA and GSH-Fc at the IIA subdomain. The binding constant and binding sites were obtained by linear sweep voltammetry and had values of 1.71×106 L·mol-1 and 1.30, respectively. Fluorescence spectroscopy methods were employed to investigate the interaction between GSH-Fc and BSA as well. Results showed that the fluorescence of BSA was quenched by GSH-Fc during a static quenching process. The binding constant and the number of binding sites were obtained and had values of 2.74×106 L·mol-1 and 1.57, respectively, which agreed well with results fromelectrochemical experiments.

Correlation energy contributions of the —CH3, —CH2— and —F functional groups in linear alkyl fluorides CH3(CH2)mF (m=0-5) were calculated and studied at MP2-OPT2/6-311++G(d) level using Meld program. We found that with an increase in the number of intervening methylene groups in the studied systems, values of Ecorr(—F) and Ecorr(—CH3) decreased in the CH3(CH2)mF (m=0-5) series. Values of Ecorr(—CH2—) are different in different positions with respect to the —F group in the system. The value of Ecorr (—CH2—) for the α position is larger than the values for methylene groups in other positions within the same system. The farther the —CH2— is from the —F group in the molecule, the smaller the value of Ecorr(—CH2—) is in CH3(CH2)mF (m=1-5) systems. We predict that with an increase in the number m in the system, values of Ecorr (—CH2—), which are those of—CH2—groups relatively far fromthe terminal —F group, would converge to the value of a“standard”—CH2—group. This Ecorr(—CH2—) value is transferable between CH3(CH2)mF homolo us systems. Results for CH3(CH2)mF (m=2-5) systems from Meld program at MP2-OPT2/6-311++G(d) level and results for CH3(CH2)mF (m=2-10) systems from Gaussian 98 program at MP2/6-311++G(d)//HF/6-311++G(d) level showthat the total correlation energy is a linear function of (m-1), where m is the number of methylene groups in the system.

Density functional theory (DFT) was applied to study the distribution of framework aluminum atoms at nine inequivalent T sites and the acidity of Brφnsted acid sites in Beta zeolite. The calculation was carried out at B3LYP/6-31G (d,p) level based on the 8Tclustermodel. According to the calculated Al/Si substitution energies, (Al, H)/Si substitution energies, proton affinities and the adsorption energies of ammonia (NH3), we propose that the most favorable sites for Al substitution and Brφnsted acid sites are at the T5 and T6 sites. The acidity of Al5-O14-Si9 is the highest among the preferred Brφnsted acid sites and the Al7-O3-Si1 site is the lowest.

Ground state geometries of a series of 1, 8-naphthalimide derivatives were calculated by density functional theory (DFT). Their UV-Vis absorption spectra in gaseous, C6H12 (cyclohexane) and CH2Cl2 environments were calculated by the time dependent-DFT (TDDFT) method and the conductor polarizable continuummodel-TDDFT (CPCM-TDDFT) method. We found that theoretical values were in od agreement with X-ray geometric parameters. The addition of various substituents (H, methyl, phenyl, and naphthyl) to the 4 and 5 positions of the naphthalic ring's amines lengthened the (N—C) bond length between the amine and the naphthalimide moiety. This bond lengthening resulted in more intramolecular charge transfer and a lower energy gap. Both the bathochromic effect and the frontier orbital electron cloud density showed that the absorption maximum corresponds to a π-π* transition. By comparison to the maximumabsorption peak of UV-Vis absorption spectrumof the B isomer, that of the A isomer was red shifted and this was mainly attributed to more intramolecular charge transfer and a lower energy gap.

Two novel heteroaromatic push-pull fluorescence polymers poly [(2,5-diphenylene-1,3,4-oxadiazole)-4,4'-vinylene-alt-N,N'-bis(4-phenylenevinylene)-phenylamine] (P1) and poly [(2,5-diphenylene-1,3,4-oxadiazole)-4,4'-vinylene-alt-N-ethyl-3,6-carbazolevinylene] (P2) were synthesized by the Wittig reaction and the Heck reaction. Polymers P1 and P2 have decomposition temperatures of 373 and 412 ℃, respectively, and exhibit od thermal stabilities. Their electrochemical properties were explored by cyclic voltammetry. The highest occupied molecular orbital (HOMO) energy levels of P1 and P2 were -5.39 and -5.81 eV, respectively, and the lowest unoccupied molecular orbital (LUMO ) energylevels of P1 andP2were -2.81and-3.09eV, respectively. Three-photon and two-photon upconversion fluorescence spectra of both polymers were measured using a femtosecond Ti:sapphire that was pumped by a femtosecond laser at 1250 and 800 nm. Strong three-photon upconversion fluorescence with maximumemission wavelengths of 510 nm for P1 and 491 nm for P2 in THF solution were observed. By pumping at 800 nm, strong two-photon upconversion fluorescences at 511 nmfor P1 and 495 nmfor P2 in THF were measured.Maximumpeaks of single-photon fluorescence in THF were at 503 nmfor P1 and at 475 nmfor P2 with fluorescence quantumyields of 0.80 for P1 and 0.31 for P2. The effect of solvent polarity on multi-photon fluorescence was studied. Increased solvent polarity were found to induce a marked red-shift of the emission band in polymers P1 and P2.

A poly-phenylenevinylene derivative (poly (2,5-dioctyloxy)-p-phenylene vinylene) (DOO-PPV) with a high degree of physical crosslinking (designated the gelation of DOO-PPV) was synthesized and characterized. Analyses of the Fourier transform-infrared (FT-IR) and the Fourier transform-Raman (FT-Raman) spectra indicate that the chemical structure of the gelation of DOO-PPV is accordant with short chain linear molecule of DOO-PPV. Photoluminescence spectra of a thin film, short chain linear molecule, and solid gelation show that the ratio of the intensity at the short wavelength emitting band and at the long wavelength emitting band decreases gradually, the ratio is 3.24, 1.10 and 0.47, respectively. Analysis of X-ray diffraction (XRD) indicated that the existence of a more oriented structure in the gelation of DOO-PPV compared with the short chain molecule and the thin film. This result suggests that interchain and self intrachain aggregations play an important role in the photoluminescence.

Two nickel coordination complexes [Ni3 (btc)2 (H2O)14]·4H2O(1), [Ni2 (btec) (bipy)2 (H2O)6]·2H2O(2), (H3btc =1,3,5-benzenetricarboxylic acid, H4btec = 1,2,4,5-benzenetetra carboxylic acid, bipy =2, 2'-bipyridyl) were synthesized hydrothermally and characterized by single crystal X-ray diffraction (XRD), infrared (IR) and Ultravialet-Visible-Near Infrared (UV-Vis-NIR) spectra. Result indicate that complex (1) is a trinuclear complex bridged by btc groups and complex (2) is a binuclear complex connected by btec groups. The existence of hydrogen bonds allows complexes (1) and (2) to become coordination supramolecules with three dimensional (3D) and two dimensional (2D) infinite structures, respectively. Surface photovoltage spectrum(SPS) of these complexes exhibits positive surface photovoltage responses from300-800 nm. However, the intensity, position and shape of these response bands are obviously different. This distinction might be responsible for the structures and coordination environments of nickel ions in these complexes. By contrasting SPS with UV-Vis-NIR spectra we find that these response bands in SPS are consistent with absorption peaks in the UV-Vis-NIR spectra.

Using Hendricks's model as initial structure, a molecular dynamics simulation without crystallographic restrictions was used to investigate the kaolinite-water systemwith the CLAYFF force field. Results showthat interlayer water molecules have three types: type I is similar to Costanzo's“hole water”molecule and its HH vector (a vector from one hydrogen atompointing to another hydrogen atomin water molecule) is parallel to the (001) plane while its C2-axis is slightly sloped and is nearly normal to the (001) plane; type II is similar to“associated water”where one O—H bond points to its neighboring layer tetrahedral oxygen and its hydrogen forms hydrogen bonds with oxygen while the other O—Hbond is approximately parallel to the (001) plane; type III watermolecule approximates a vertical form where one hydrogen forms a bond with tetrahedral oxygen and the other forms a hydrogen bond with a hydroxyl oxygen in the opposite clay layer. The concentration curve of the hydroxyl hydrogen of kaolinite along the normal line of the (001) plane shows that a portion of the hydroxyls change their orientation to be nearly parallel to the (001) plane. The corresponding oxygen atoms in the hydroxyl can therefore be exposed and forma hydrogen bond with interlayer water. Furthermore, some oxygen atoms of Type II water molecule deviate from their average position in the interlayer space and are closer to the tetrahedral layer and this result is consistent with Costanzo's result and may be the reason for the weak (002) peak observed in X-ray diffraction.

Arrayed porous titaniumdioxide loaded on titanium(TiO2/Ti) was fabricated using the sol-dipping method with polystyrene sphere (PS) arrays as a template. Its morphology and crystal phase composition were characterized by SEM and XRD, and its photoelectrocatalytic performance was studied using open-circuit potential curves, photocurrents with intermittent irradiation, degradation of methyl orange and hydrogen-evolution overpotential. Results show that arrayed porous TiO2/Ti has high catalytic activity because of the photoelectro-synergisitic effect. The degradation rate of methyl orange was 87.1% after reaction for 2.5 h and 97.9% after reaction for 5 h, and it has an apparent reaction rate constant of 0.77 h-1. The hydrogen-evolution overpotential on this material was reduced from -0.81 V to -0.68 V under ultraviolet irradiation.

The structure and performance of Sm0.5Sr0.5Co0.4M0.6O3(M=Co, Mn, Fe|denoted SSCC, SSCM and SSCF, respectively) as intermediate temperature-solid oxide fuel cells (IT-SOFCs) cathodes were investigated by X-ray diffraction (XRD), thermogravimetry (TG), thermal expansion, electrical conductivity and electrochemical impedance spectroscopy (EIS). The Sm0.5Sr0.5Co0.4M0.6O3 system has an orthorhombic structure. The crystal parameter increases in the following order: Co, Mn, Fe, while the oxygen content, thermal expansion and electrical conductivity decrease in the same order. The electrocatalytic activity of SSCMcathodes is limited by the oxide ion diffusion process because of low oxide ion vacancy, while the electrocatalytic activity of SSCC or SSCF is controlled by an oxygen exchange process on the cathode surface and an oxide ion diffusion process in the cathode because of the high oxide ion vacancy. The area specific resistance (ASR) of SSCF is lower than that of the SSCC above 700 ℃ because of the high oxide diffusion coefficient of SSCF, so the total electrocatalytic activity of SSCF is higher than that of SSCC.

Aggregation behavior of the room temperature ionic liquid (IL) [C4mim][BF4] in D2O and CDCl3 was studied by the nuclear magnetic resonance (NMR) technique. Results indicated that proton chemical shifts for the cation of the IL shift downfield as the molar fraction of IL increases. These proton chemical shifts change rapidly at lower concentrations and level off at higher concentrations in D2O. Chemical shifts for H2 on the cation shift upfield. H4, H5, methyl and methylene protons next to the nitrogen of the cation shift downfield as the molar fraction of IL increases while the NMR signals for each proton changes in CDCl3. The critical aggregation concentration (CAC) and the aggregation number were determined by applying mass action theory to the concentration dependence of the 1H NMR chemical shifts. These results are discussed based on the interactions between the cation and the anion and those between the IL and the solvents.

The electrocatalytic activity of a roughened silver electrode towards the reductive dehalogenation of 2,4,6-tribromophenol was compared to a glassy carbon electrode and a polished silver electrode in basic aqueous solution by cyclic voltammetry (CV). Furthermore, the course of reductive dehalogention of 2,4,6-tribromophenol was studied by CV and controlled-potential electrolysis. Results indicated that roughened silver exhibited more powerful electrocatalytic activity than the glassy carbon electrode and the polished silver electrode for the selective dehalogention of 2,4,6-tribromophenol. The reduction of 2,4,6-tribromophenol was determined to be a stepwise dehalogenation as follows: 2,4,6-tribromophenol→2,4-dibromophenol→2-bromophenol→phenol. In addition, the activity energy needed for the dissociative reduction of the ortho carbon-halogen bond was similar to the para carbon-halogen bond for 2,4,6-tribromophenol and a higher energy was probably required for 2,4-dibromophenol to cleave the ortho carbon-halogen bond compared to the para carbon-halogen bond.

Adsorption of CO onto Pdn (n=1-8) clusters was systematically investigated using density functional theory. Results indicate that the lowest energy structures of PdnCO are still generated when CO is adsorbed onto Pdn clusters. We found that among the molecular adsorption states, a weakly bound state with end-on type geometry is the most energetically favorable. The lowest energy structures of Pdn clusters are not changed by adsorbing CO molecules. Chemisorption of CO onto Pdn cluster surfaces is a non-dissociative adsorption process. An increased theoretical CO bond length of 0.1167-0.1168 nm in PdnCO cluster (compared to 0.1166 nm in free CO molecule) indicates a small activation for the CO bond except for the case where n=2. Natural bond orbital analysis shows that the interaction between a Pd atom and a CO molecule is small. The second-order energy difference shows that Pd4CO and Pd6CO clusters have enhanced stabilities.

CdTe quantum dots (QDs) with fantastic optical properties were synthesized in an aqueous solution by thiol ligands. Reaction conditions, such as Cd-to-ligand molar ratio and precursor concentrations, were optimized to well control the QD size and to achieve high quantum yield (QY). High quality water-dispersed CdTe QDs (QY 45%) were obtained in a hydrothermal systemand the QD emission wavelength ranged from 485 to 660 nm detected at room temperature. The full width at half maximum (FWHM) of the emission peaks broadened from 40 to 75 nm. Thiourea was innovatively utilized to chemically modify the surface of CdTe by the hydrolysis and photolysis of thiourea which can release free sulfide ions. The changes in optical properties of these treated QDs were monitored within 12 days. When n(CdTe)/n(thiourea)=1:4 (concentration of QDs according to the cadmium ion concentration), the fluorescence intensity of the CdTe QDs (λex= 505 nm) increased 5 times. The QY increased to 68.3%.

A phosphorylated sodium alginate (P-SA) membrane was synthesized using phosphorus pentaoxide, riethyl phosphate and phosphoric acid and then modified by ferrocene. Chitosan (CS) was modified by acetylferrocene. A P-ferrocene-SA/acetylferrocene-CS bipolar membrane, P-mSA/mCS BPM, was prepared by a paste method. The bipolar membrane was characterized by Fourier transform infrared spectroscopy (FTIR), contact angle, charge density, ion exchange capacity and alternating current impedance spectroscopy. Results of FTIR and contact angle measurements showed that the hydrophilic property of SA improved after modification by phosphorylation. P-mSA/mCS BPMwas applied to separate monovalent and divalent ions. The rejection ratios of divalent and monovalent ions were about 95%and 22%, respectively, when the pressure was 0.3 MPa.

In this paper, the space charge capacitance of a bipolar semiconductor passive filmwas considered to be equivalent to a series connection of a capacitance at the passive film/solution interface and an np-junction capacitance at the outer layer film/inner layer film interface. Based on a uniform expression established in our previous work, a non-linear method was used to fit the Mott-Schottky (M-S) plots of bipolar semiconductor passive films. We then investigated the semiconductor characteristics of passive films formed on the surface of the nickel base alloy G3 after environmental corrosion at high temperatures and high partial pressures of H2S/CO2 using this method. Fitting results of measured M-S plots indicated that the majority carrier density of the p type semiconductor outer layer of the bipolar passive film obviously increased as the temperature increased while the majority carrier density of the n type semiconductor inner layer was almost unchanged. The fitting results show that the non-linear fitting method can produce multiple semiconductor characteristic parameters of the inner/outer layer of bipolar passive films. From these fitting results a mechanism for the formation and breakdown of passive films was established. A variable mechanism for the passive film structure and the role of the np-junction in the corrosion inhibition process were discussed by considering X-ray photoelectron spectroscopy (XPS) results as well.

Effects of Ho3+ ion modification on photoelectrical properties of TiO2 electrodes were investigated. On the one hand, the Ho3+ layer decreased electron injection between the dye and TiO2, but on the other hand, it suppressed charge recombination. Experimental results showed that an energy barrier was formed when the TiO2 electrode was modified with a Ho3+ layer of a certain thickness. This energy barrier efficiently suppressed charge recombination. As a result, the photovoltage and photoelectrical conversion efficiency were improved under optimal conditions. Photoelectrical conversion efficiencies of TiO2/Ho-0.1 and TiO2/Ho-0.2 (0.1 and 0.2 are the concentrations of Ho3+ solution used for modification, mol·L-1) electrodes reached 8.3%and 7.6%, respectively, under illumination with white light at 93.1 mW·cm-2. This represents an increase of about 15% and 5%, respectively, compared to a bare TiO2 electrode (7.2%).

Soil colloidal aggregation kinetics was studied at different concentrations of KNO3 and Mg(NO3)2 by dynamic light scattering. By analyzing the change in light intensity and effective diameter of aggregates with time, we conclude that: (1) The stability of the light intensity in an aggregation process is a basis for judging if the collision is dominated either by Brownforce or gravity; (2) With different electrolyte systems, soil colloidal aggregation exhibits a fast diffusion-limited cluster aggregation (DLCA) character or various slowreaction limited cluster aggregation (RLCA) characters and a gravity sensing electrolyte concentration exists in RLCA; (3) The aggregation characters induced by two electrolytes are essentially similar but the aggregating process is more sensitive to the Mg(NO3)2 electrolyte concentration change than to KNO3. By analyzing the change of average aggregation velocity with electrolyte concentration, the turning point where electrolyte concentration changes from slow to fast aggregation is designated as the critical flocculation concentration (CFC). A new method for measuring the CFC experimentally is thus provided.

Hydrothermal methods were used to prepare doped LiMxMn1-xO2(M=Mg, Y, Zr) as cathode materials for lithium-ion batteries. The structure and morphology of the as-prepared cathode materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The effects of ion doping on the performance of orthorhombic materials was analyzed in terms of their crystal structure, charge-discharge curves, cycle performance and electrochemical impedance spectroscopy (EIS). Results show that the doped materials had better cycle performance. In particular, the discharge capacity of Li0.99Mn0.979Y0.021O2 remains 226.3 mAh·g-1 after 60 cycles with a current density of 50 mA·g-1 at roomtemperature.

Co(bpb) [bpbH2 is N,N'-o-phenylenebis(pyridine-2-carboxamide), C18H12N4O2] complex has active axial sites like a porphyrin complex. We studied the coordination of azide ion (N-3) to Co(bpb) in binary methanol-water mixtures by spectrophotometric method at the temperature range of 283-303 K. From the temperature dependence of the rate constant, activation parameters (Ea, △H#, △S#, and △G#) were obtained. An isokinetic temperature at about 302 K was observed at which the formation rate of Co(bpb)-N-3 was more or less independent of the solvent composition. The resulting △H against T△S plot showed a od linear correlation, indicating the existence of enthalpy-entropy compensation in azide complexation process. Under optimum conditions and based on the absorbance of Co(bpb)-N-3 produced through complex formation, a spectrophotometric method for the determination of N-3 in solution was developed.Alinear relationship between the absorbance and N-3 concentration was obtained in the range of (0.85-5.00)×10-4 mol·L-1 (3.6-21.0 μg·mL-1). The detection limit was 2.5×10-5 mol·L-1 (1.0 μg·mL-1). The proposed method was applied to the determination of N-3 anion in real water samples.

Mainland China contributed to progress in several fields of theoretical chemistry in 2008. These fields include the method and application of density functional theory, chemical reaction dynamics and construction of potential energy surfaces, photochemistry, biological molecules and life phenomena, and stereochemistry. This progress has been reviewed in this paper and several important contributions are highlighted.