The ultrafast internal conversion of benzyl chloride (BzCl) was studied with femtosecond time-resolved photoelectron imaging (TRPEI) coupled with time-resolved mass spectroscopy. Time-energy maps of the photoelectron intensity and the angular anisotropy were generated from a series of photoelectron images. Upon absorption of two 400 nm photons, benzyl chloride was excited to the S₄ and S₂ states at the same time. The time evolution of the parent ion with different pump-probe delays can be well described by biexponential decay. The fit yielded τ₁=50 fs and τ₂=910 fs. By analysis of time-resolved photoelectron kinetic energy distributions, it is concluded that the excited S₄ state has coupled with and decayed to the S₂ state in a short time scale and then converted to the S₁ state through ultrafast internal conversion (IC). Within 50 fs, the molecule electronically relaxes into S₁ through IC and from there, decays to the S₀ ground state with the relatively slow time constant of 910 fs. The anisotropy parameters of photoelectron angular distributions changed from 0.87 at the delay time of 0 fs to 0.94 at 25 fs and then to 0.59 at 190 fs, which also reflects the coupling from the S₄ state to the S₂ state and the following IC to the S₁ state.

Surface-enhanced Raman spectroscopy (SERS) on silver nanoparticles is highly sensitive because of surface plasmon resonance. We have studied the structures and photoinduced chemical reactions of p-chloronitrobenzene (PCNB) molecules adsorbed on silver nanoparticles using a combination of SERS and density functional theory (DFT) calculations. When the PCNB molecules are adsorbed to the surface of silver nanoparticles in alkaline solution, the SERS spectra are very different from the normal Raman spectra of PCNB. Comparison of the DFT simulated Raman spectra of PCNB and p,p'-dichloroazobenzene (DCAB) indicates that the new peaks in the SERS spectrum of PCNB adsorbed on silver nanoparticles arise from the azo (C－N＝N－C) group of DCAB.

Two new types of Salen-porphyrin ligand and metal complexes with π-conjugate configurations were synthesized. The mono- and bi-nuclear nickel Salen-porphyrin complexes were synthesized from half Salen-porphyrin ligands and the corresponding aldehyde by metal templating. Based on the mononuclear nickel Salen-porphyrin complexes, the heterobinuclear nickel, zinc Salen-porphyrin complexes were synthesized. All the compounds were characterized by proton nuclear magnetic resonance (¹H NMR), ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, electron spray ionization mass spectrometry (ESI-MS), and fluorescence spectroscopy. These results indicate that the nickel ion is located in the cavity of the Salen part, while the zinc ion is located in the center of the porphyrin part of the mononuclear nickel and heterobinuclear nickel-zinc Salen-porphyrin complexes. The circumfluent effect of the porphyrin and the π-conjugate configuration resulted in the chemical shifts of the hydrogen atoms moving to a higher or lower field. The positions of the Soret and Q bands in the UV-Vis spectrum of the porphyrin change after the metal ion coordinated. Furthermore, the fluorescence quenched due to the metal ion.

Three lanthanide-based supramolecular compounds, [Ln(HBIC)₃]_n [Ln=Sm (1), Ho (2), Yb (3); H₂BIC=1H-benzimidazole-2-carboxylic acid], were hydrothermally synthesized and structurally characterized by X-ray single crystal diffraction (compounds 1 and 2), powder X-ray diffraction (XRD) (compound3), elemental analysis, infrared (IR) spectroscopy, and thermal analysis. Structural analyses reveal that compounds 1-3 are isomorphous and display a two-dimensional (2D) plane, in which each lanthanide center is coordinated by three N and five O atoms from five flexible HBIC^- ligands with two kinds of new coordination modes, giving rise to a slightly distorted two-capped triangle prism geometry. The 2D square networks are further assembled into a three-dimensional (3D) supramolecular framework through strong hydrogen-bonding interactions. Thermogravimetry analyses (TG) indicate that compounds 1-3 exhibit od thermostability and could be stable up to 360℃. By means of differential scanning calorimetry (DSC) techniques, the thermoanalysis kinetics parameters of the thermodecomposition of compound 1 were calculated by the Kissinger's and Ozawa-Doyle's methods; the pre-exponential factor A_K was 1.286×108 s^-1 and the apparent activation energy E_K and E_O were determined to be 199.3 and 205.2 kJ·mol^-1, respectively. In addition, the luminescent properties of compounds 1 and 3 were also studied at room temperature in the solid state. The results reveal that compounds 1 and 3 exhibit characteristic emission bands of the corresponding lanthanide ions in the visible and near-infrared regions, respectively.

To build the quantitative structure-property relationship (QSPR) between the molecular structures and the thermal conductivities of 147 organic compounds and investigate which structural factors influence the thermal conductivity of organic molecules, the topological, constitutional, geometrical, electrostatic, quantum-chemical, and thermodynamic descriptors of the compounds were calculated using the CODESSA software package, where these descriptors were pre-selected by the heuristic method (HM). The dataset of 147 organic compounds was randomly divided into a training set (118), and a test set (29). As a result, a five-descriptor linear model was constructed to describe the relationship between the molecular structures and the thermal conductivities. In addition, a non-linear regression model was built based on the support vector machine (SVM) with the same five descriptors. It was concluded that, although the fitting performance of the SVM model (squared correlation coefficient, R²=0.9240) was slightly worse than that of the HM model (R²=0.9267), the predictive performance of the SVM model (R²=0.9682) was better than that of the HM model (R²=0.9574). As the predictive parameter is more important than the fitting parameter, it can be seen that the SVM model is superior to the HM model. The proposed methods (SVM and HM) can be successfully used to predict the thermal conductivity of organic compounds with pre-selected theoretical descriptors, which can be directly calculated solely from the molecular structure.

In order to dynamically track the trajectory of diffusing molecules in a chromatography system, and to thoroughly understand its influence on chromatographic dynamics, we have developed software based on the framework of random walks in a confined space, with which the diffusion processes have been simulated. The influence of the filling rates, the form of the stationary phase, and the column length of a packed column on the chromatographic dynamics have been discussed based on these simulation results. It was concluded that shorter column lengths and larger filling rates result in a higher column efficiency. The particles to be separated normally show basic diffusion characteristics in the confined space. However, their flow behavior will increase with increasing external pressure. The simulation results indicate that the influence of the filling rate of the stationary phase and the column length on chromatographic dynamic behavior is similar to those seen in experiment, whereas the form of the stationary phase only has a slight effect because of the same close-packed barrier arrangement. This simulation method we proposed has some significance for the development of high-performance chromatography and novel separation technologies.

We performed a semiclassical dynamics simulation study of the photophysical deactivation of 5m-cytosine (5m-Cyt) and cytosine (Cyt) induced by ultraviolet radiation of 267 nm. The results show that deactivation of the excited state of 5m-Cyt and Cyt results from the distortion of the C₅－C₆ bond and the out-of-plane vibration of methyl (or H₅) and the H6 atom. A so-called“biradical state”, in which the methyl (or H₅) and H₆ atoms are nearly perpendicular to the average ring plane and displaced in opposite directions, is formed at the decay point. The vibration frequency of the methyl derivative is less than that of the H atom derivative because of its increased volume relative to the H atom. The results indicated that molecular deformation at the C₅ atom of 5m-Cyt will be weakened and will result in a longer excited lifetime of 5m-Cyt. Complete active space self-consistent field (CASSCF) calculations show that the energy of the conical intersection (CI) of 5m-Cyt is 0.3 eV higher than that of Cyt. This suggests that promotion to the CI point for 5m-Cyt requires the molecule to overcome a larger energetic barrier, which results in a longer excited state lifetime than Cyt.

Theoretical calculations on a series of N－H…O＝C hydrogen-bonded complexes containing 1-methyluracil and N-methylacetamide were carried out using B3LYP and MP2 methods. Substituent effects in the hydrogen bond acceptor molecule (1-methyluracil) on the hydrogen bond strength and hydrogen bond cooperativity were explored. The calculation results show that electron donating groups shorten the H…O distance and strengthen the N－H…O＝C hydrogen bond, whereas electron withdrawing groups lengthen the H…O distance and weaken the N－H…O＝C hydrogen bond. Natural bond orbital (NBO) analysis further indicates that electron donating groups result in a larger positive charge on the H atom and a larger negative charge on the O atom in the N－H…O＝C bond, and result in increased charge transfer between the proton donor and acceptor molecules. Electron withdrawing groups show the opposite results. NBO analysis also indicates that electron donating groups result in larger second-order interaction energies between the oxygen lone pair and the N － H antibonding orbital when compared to the 1-methyluracil-containing complex (R=H), while electron withdrawing groups result in smaller second-order interaction energies.

Using the second-order Møller-Plesset perturbation method, the structures and π-lithium bonding properties of C₂H_4-nF_n···LiH (n=0, 1, 2) dimers were analyzed. The results showed that F substitution led to π electron cloud deformation in the ethylene molecule, and subsequent changes (deviation, elongation, and bend) in the π-lithium bonds in C₂H_4-nF_n···LiH. In contrast to the π-hydrogen bonds in the C₂H_4-nF_n···LiH (n=0, 1, 2) systems, the π-lithium bonds in the C₂H_4-nF_n···LiH dimers were obviously bent because of secondary hydrogen bond interactions, and they exhibited weak directivity. For the four C₂H_4-nF_n···LiH dimers, the strength of the interaction was 33.85 kJ·mol^-1 (C₂H₄-LiH)>27.32 kJ·mol^-1 (C₂H₃F-LiH)>21.34 kJ·mol^-1 (cis-C₂H₂F₂-LiH)>20.25 kJ·mol^-1 (g-C₂H₂F₂-LiH) at the CCSD(T)/6-311++G(3df, 3pd) level. This indicates that the F substituent effect decreases the strength of the interaction between ethylene and LiH molecules.

The isodesmic reaction method is proposed for the accurate calculation of the reaction barriers and rate constants for an important class of reactions in the high-temperature combustion mechanism: the pyrolysis of alkyl radicals in the β position. The reaction barriers were calculated for a representative set of five reactions by two schemes: the first scheme is to calculate the reaction barriers directly from approximate ab initio calculations; and the second scheme is to correct the reaction barriers from the first scheme using the isodesmic reaction method. Ten different levels of ab initio calculations were used, and the absolute average maximum deviations of the reaction barriers by the isodesmic reaction method and direct ab initio calculations were 5.32 and 16.16 kJ·mol^-1, respectively, indicating that the isodesmic reaction method does not significantly depend on the level of ab initio theory used. The rate constants of the three representative reactions in the temperature range of 500-2000 K were calculated by the isodesmic reaction method. The average and maximum values of k_max/k_min between the calculated and experimental values were 1.67 and 2.49, respectively. Therefore, the isodesmic reaction method is efficient and reliable for the calculation of the reaction barriers and rate constants of reactions in a class at a modest level of ab initio theory.

Density functional theory calculations at the B3LYP/6-311 ++ G(d,p) level were performed to study the reaction mechanism and potential energy surface of the 1,2- and 1,4-addition reactions between silabenzenes and HX (X=F, OH, NH₂). The influences of substituents at the Si atom and tetrahydrofuran as a solvent on the potential energy surfaces of the reactions were also explored. The results indicated that the title reactions occur by the following two mechanisms: (1) silabenzene and one HX molecule form an intermediate complex, and then isomerize to give final product via a four-membered transition state; and (2) silabenzene and two HX molecules form an intermediate complex, and then isomerize via a sixmembered transition state to give another intermediate complex from which one HX molecule is left to afford the final product. Mechanism 2 is much more favorable than mechanism 1 kinetically. The preference for the 1,2- or 1,4-addition product is determined by kinetics and is related to the X group. The reactivity order of HX toward the addition reaction with silabenzene in gas phase is HF>H₂O>NH₃. Strong electron-donating and -withdrawing substituents at the Si atom have a favorable influence on the potential energy surfaces of the 1,2- and 1,4-addition reactions, while the large mesityl group has the opposite effect. Tetrahydrofuran has an unfavorable thermodynamic influence on the reactions, and kinetically on those reactions with HF or H₂O. However, it favors the reactions between silabenzenes and NH3 kinetically.

The polarizabilities (α_s) and second hyperpolarizabilities (γ_s) of a series of 6,12-diethynylindeno[1,2-b]fluorene derivatives were investigated by the density functional theory CAM-B3LYP method. The calculated results indicate that these molecules possess considerably large second hyperpolarizabilities. Replacing the 6,12-hydrogen atoms on indeno[1,2-b]fluorene molecules by ethynyl silyl or oxygen atoms results in a change in the geometry of the molecular structure, which affects the nonlinear optical (NLO) properties. Introducing ethynyl silyl groups into the molecules can increase the α_s and γ_s values, while these values decrease introducing oxygen atoms into the molecules. Also, the γ_s values depend on the 2, 8-disubstituted R groups (R=H, F, CH₃) of the indeno[1,2-b]fluorene molecules. When R is methyl, the molecule has much larger α_s and γ_s values. Moreover, according to time-dependent density functional theory calculations on the indeno[1,2-b]fluorene series, the maximum absorption wavelength of the ethynyl silyl derivatives display a bathochromic shift due to increasing conjugation, while a blue shift of the maximum absorption wavelengths are observed in the oxygen-substituted derivatives because the conjugation decreases as the molecular structure is distorted.

Based on first-principles within the density functional theory, the geometric structures of perfect zinc blend ZnSe, that with Zn vacancies (Zn_0.875Se) and Cu-doped ZnSe(Zn_0.875Cu_0.125Se) were optimized using the plane-wave ultrasoft pseudopotential method. The defect formation energy, band structure, density of states, mulliken charges, and optical spectra were calculated and discussed in detail. The results demonstrated that in Zn_0.875Se and Zn_0.875Cu_0.125Se systems, because of the introduction of the vacancy acceptor level or acceptor impurity level, the band gap is reduced, and the absorption peaks show a remarkable redshift. Cu doping into the ZnSe system was found to be relatively stable, while the monovacancy system was not.

A quasi-solid-state three-dimensionally crosslinked poly(citric acid-ethylene glycol) (PCE)/ LiI/I₂ polymer electrolyte has been prepared using biodegradable PCE synthesized via a crosslinking reaction between citric acid (CA) and oli -polyethylene glycol (PEG) (average molecular weight M_w= 200, 400, 1000, 2000) as a matrix. The molecular structure of the PCE matrix, micro-morphology of polymer electrolyte, and the state of conductive ion-pairs in the electrolyte were characterized by infrared (IR) spectrum, 1H nuclear magnetic resonance (1H-NMR), and Raman spectroscopy, as well as scanning electron microscopy (SEM). The ionic diffusion coefficient and conductivity of polymer electrolytes and the output current-voltage (I-V) properties of the cells were investigated via linear sweep voltammetry. The results reveal that PEG molecular weights influence the mesh morphology and the absorbent properties of the PCE matrix, which influences the polymer electrolyte ionic conductive performance and the photoelectric performance of the cells. As PEG molecular weights increased from 200, 400, 1000 to 2000, the PCE matrix mesh structure became looser, the liquid electrolyte uptake of the matrix increased, and the transition activation energies of I₃^- in the swollen PCE matrix decreased, which led to an increase in the electrolyte conductivity and the short circuit photocurrent densities of the cells accordingly. The photoelectric conversion efficiencies of the cells assembled by the four polymer electrolytes above were 3.26%, 3.34%, 4.26%, and 4.89%, respectively, under an incident light intensity of 60 mW·cm^-2.

Highly ordered ZnO nanorod arrays were prepared on an indium-tin oxide (ITO) glass substrate using an electrochemical method. The poly(3-hexylthiophene) (P3HT)-modified CdS/ZnO shellcore nanorod arrays were fabricated by electrodepositing CdS nanoparticles and then a thin P3HT layer onto the prepared ZnO nanorod arrays. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and energy dispersive X-ray spectroscopy (EDX) were used to characterize the samples to confirm the formation of the designed nanostructures. A semiconductorsensitized solar cell with the designed nanostructure as the photoanode was fabricated. The effects of the thickness of the CdS layer and the deposition of the P3HT layer on the photovoltaic performance of the designed solar cell were investigated, as well as the charge transfer mechanism of the solar cell. The results indicated that light absorption of the photoanode was broadened to the visible region through the electrodeposition of the CdS nanoparticles and P3HT film onto the ZnO nanorods. An energy conversion efficiency up to 1.08% was obtained with the designed semiconductor-sensitized solar cells.

Nano-carbon aerogels (CA) were prepared by the reaction between resorcinol and formaldehyde in alkaline conditions. The morphology and microstructure of the CA was investigated by scanning electron microscopy and transmission electron microscopy. The specific area and the pore size distribution were calculated from the N₂ adsorption-desorption isotherm. Glucose oxidase ( D)/CA/ glassy carbon (GC) electrodes were prepared by immobilizing D on the surface of nano-carbon aerogels. The electrocatalytic properties of D/CA/GC electrodes were characterized by cyclic voltammetry in phosphate buffer medium (0.1 mol·L^-1). The results showed that D can be immobilized on the nano-carbon aerogels, and that the biological activation of D was retained. The D/CA/GC electrode exhibits od direct electrochemical and electro-catalytic performance without electron mediators.

Cobaltate nickel (NiCo₂O₄) microbelts were fabricated by direct calcination of electrospun precursor samples with an appropriate heating rate. The crystal structure, morphology, magnetic properties, and electrochemical properties of the NiCo₂O₄ microbelts were investigated by X-ray diffraction, scanning electron microscopy, vibrating sample magnetometry, and electrochemical analysis. The results showed that a heating rate of 1℃·min^-1 resulted in the formation of cubic spinel NiCo₂O₄ microbelts. After calcination at high temperatures, the microbelts retained their one-dimensional structure. Magnetization results indicated that the NiCo₂O₄ microbelts were superparamagnetic and their magnetization value at 10 kOe was 6.35 emu·g^-1. Moreover, the electrochemical results suggest that the capacitance of the NiCo₂O₄ microbelts is typical pseudocapacitive capacitance, and the value of the specific capacitance gradually decreases with increasing discharge current density.

40% (w) Pt/graphene composites were prepared by sodium borohydride chemical coreduction, and were subsequently used as an electrocatalyst for oxygen reduction reactions. The electrocatalytic activity and stability was evaluated by cyclic voltammetry. The results indicated that the initial activity of Pt/graphene was lower than that of Pt/C due to the oxygen diffusion inhibition; however, the Pt/graphene showed superior durability characteristics. Degradation tests showed a 50% degradation of Pt/ graphene, which was substantially less than that of Pt/C (79%). X-ray diffraction and transmission electron microscope results showed that the composite formed strong interactions between the platinum nanoparticles and the graphene supports. The graphene supports may also prevent the graphene sheets from folding or re-stacking, which would hinder platinum nanoparticles' aggregation. The performance of a single cell was also tested, confirming an improvement in durability.

The low tap density of LiFePO₄ is hindering the energy and power density of lithium-ion batteries in portable electronics, electric vehicles, and stationary electricity storage applications. As part of our work to investigate the pathological mechanism of performance degradation in large particle LiFePO₄, micro-sized pristine LiFePO₄ without modifications, such as surface coating or bulk doping, was first prepared hydrothermally by optimizing the synthesis parameters in this work. The influences of precursor concentration, solution pH, hydrothermal temperature, and heating time on the phase structure, particle size, and morphology of the products were systematically investigated. It was found that the particle size of LiFePO₄ increases with decreasing pH value, increasing precursor concentration, increasing hydrothermal temperature, and increasing heating time during hydrothermal synthesis. The performance degradation of large particle LiFePO₄ was demonstrated by these intrinsic samples. The specific discharge capacity decreased from 152 to 80 mAh·g^-1 at 0.1C rate when the particle size was increased from 0.7 to 16.5 μm. Moreover, less capacities were retained after 100 cycles at 1C rate for larger particle materials. Finally, the optimized LiFePO₄ with a distorted diamond shape was prepared for later investigation of the plausible mechanism of performance degradation in large particle LiFePO₄. Its electrochemical performance was preliminarily discussed, and will need to be improved in future to obtain practical high energy/power density LiFePO₄ cathodes for lithium-ion batteries.

Sn_0.9Mg_0.1P₂O₇ was synthesized in a solid state reaction and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD pattern indicated that the sample exhibited a single cubic phase. The protonic and oxide-ionic conduction were investigated using various electrochemical methods including AC impedance spectroscopy and gas concentration cells at intermediate temperatures (323-523 K). The highest conductivity observed was 5.04×10^-2 S·cm^-1 in a wet H₂ atmosphere at 423 K. The ionic, protonic, oxide-ionic, and electronic transport numbers (N_t) were 0.95-1.00, 0.84-0.96, 0.04-0.10, 0.00-0.05, respectively, in a wet hydrogen atmosphere. The results indicate that Sn_0.9Mg_0.1P₂O₇ is an almost pure ionic conductor, has dominant protonic conduction, some limited oxide-ionic conduction, but little electronic conduction. A H₂/air fuel cell using Sn_0.9Mg_0.1P₂O₇ as the electrolyte (thickness: 1.5 mm) generated maximum power densities of 18.7 mW·cm^-2 at 398 K, 27.7 mW·cm^-2 at 423 K, and 33.9 mW·cm^-2 at 448 K.

A monoclinic Li₃V₂(PO₄)₃/C cathode has been synthesized for use in lithium ion battery applications via a P123-assisted rheological phase reaction (RPR) method. Li₃V₂(PO₄)₃/C composite materials were prepared from a mixture of V₂O₅, LiH₂PO₄, LiOH, citric acid, and triblock copolymer surfactant P123. The composite material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The electrochemical performance was tested by Galvanostatic charge-discharge tests, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The P123-assisted Li3V2(PO4)3/C assumes a pure monoclinic crystal structure and exhibits a high initial discharge capacity of 128.9 mAh·g^-1, which only decreases by 0.9% of its initial value after 50 cycles at 0.1C between 3.0 and 4.3 V. Moreover, the cathode displays od fast rate performance, displaying discharge capacities of 128.2, 121.3, and 109.1 mAh·g^-1 and capacity retentions after 50 charge-discharge cycles of 99.1%, 96.9%, and 90.7% at rates of 1C, 10C, and 25C, respectively. The introduction of the triblock copolymer surfactant P123 to the RPR system is attributed to the excellent electrochemical performance. It acts as a surfactant as well as an organic carbon source, and forms a carbon network in the particle surface, which helps improve the material conductivity rate, and reduce the charge transfer resistance and electrode polarity effects during the charge-discharge process.

Batch adsorption experiments of Pb(II) and Cu(II) on kaolinite as a function of kaolinite concentration were conducted. An obvious sorbent concentration effect (C_s-effect) was observed; namely, the adsorption isotherm declines as sorbent concentration (C_s) increases. The experimental data were fitted to the classic Langmuir model. The results showed that the classic Langmuir model could adequately describe the adsorption equilibria of Pb(II) and Cu(II) on kaolinite for a given C_s value, but could not adequately predict the Cs-effect observed in the adsorption systems. We proposed a surface component activity (SCA) model. It suggests that the interactions between the sorbent particles exist in the real adsorption system, and the activity coefficient of the adsorption sites of the sorbent surface is a function of C_s. Based on the SCA model, a C_s-dependent Langmuir (Langmuir-SCA) isotherm was derived. The applicability of the Langmuir-SCA isotherm was examined with the experimental adsorption data of Pb(II) and Cu(II) on kaolinite, as well as Cd(II) and Zn(II) on vermiculite and Pb(II) on coffee reported in the literature. The results showed that the Langmuir-SCA equation could describe the C_s-effect observed in adsorption experiments. The two intrinsic parameters of the Langmuir-SCA isotherm, the thermodynamic equilibrium constant (K_eq) and the characteristic saturation adsorption capacity (Γ_m⁰), are independent of C_s and can be simulated with experimental adsorption data.

The protonated layered perovskite oxide H_1.9K_0.3La_0.5Bi_0.1Ta₂O₇ (HKLBT) was prepared from K_0.5La_0.5Bi₂Ta₂O₉ (KLBT) by H ion-exchange, and subsequently characterized by thermogravimetric analysis (TG-DSC), X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), and X-ray photoelectron spectroscopy (XPS). The effects of the calcining temperature on the material's photocatalytic activity were also investigated. Results showed that HKLBT with high crystalline quality could be synthesized at low temperatures and that HKLBT prepared from KLBT calcined at 900℃ exhibited the greatest photocatalytic activity, with an average water splitting hydrogen evolution rate of 236.6 μmol·h^-1 in pure water. The time course of water splitting indicated HKLBT has ability to split water into hydrogen and oxygen with long-term stability.

Enhanced photocatalytic activity of BiVO₄ has been achieved by immersing in HCl aqueous solution. After treated for 6 h in 0.1 mol·L^-1 HCl solution, the visible light activity of BiVO₄ for phenol degradation increased by 3.5 times. X-ray diffraction (XRD), scanning electron microscopy (SEM), and diffuse reflectance spectroscopy (DRS) were carried out to analyze the crystal components and surface morphology of the treated samples. Comparison of samples treated in different acids and chlorides indicated that with the appropriate concentrations of H⁺ and Cl^- ions, BiVO₄ partially dissolved, was deposited as BiOCl, and finally a composite of flaked BiOCl and micro-particles of BiVO₄ with pits formed over the surface. The flatband potential of BiOCl was measured by a slurry method. According to the results of energy band analyses and photocatalytic activity tests of mixed BiVO₄ and BiOCl particles, there is no interparticle electron transfer effect between them. Therefore, the mechanism of the enhanced photocatalytic performance of the treated BiVO₄ can be attributed to the unevenness of the surface, which can facilitate photogenerated charge separation. This type of surface treatment method could be developed into an effective method for preparing photocatalysts with enhanced photocatalytic performance.

Samples containing a nickel phosphide precursor were synthesized by the impregnation method using TiO₂-pillared sepiolite (Ti-Sep) as a support, nickel hydroxide as a nickel source, and phosphorous acid as a phosphorus source. From these precursor samples, Ni₂P/Ti-Sep catalysts with Ni content ranging from 5%-25% (w, mass fraction) were prepared by temperature-programmed reduction. Thiophene hydrodesulfurization (HDS) was used to investigate the HDS activity of the catalysts. The catalysts were characterized by X-ray powder diffraction (XRD), N₂ adsorption-desorption, thermal gravity analysis (TGA), transmission electron microscope (TEM), and Fourier transform infrared spectroscopy (FTIR). The results demonstrated that the specific surface area and pore volume of Ti-Sep were enlarged and catalyst thermal stability was improved. In addition, the layer spacing of sepiolite was also increased. As a consequence, the active component, Ni₂P, can be well dispersed on the interlayer and outer surface of Ti-Sep. Moreover, the layered sepiolite structure remained intact in the Ni₂P/Ti-Sep catalysts. Consequently, thiophene conversion on Ni₂P/Ti-Sep is improved compared with Ni₂P/Na-Sep (NaCl-modified sepiolite) and Ni₂P/HCl-Sep (HCl-modified sepiolite), which were prepared on sepiolite without Ti-pillaring. Ni₂P/Ti-Sep with a Ni loading of 15% (w) shows the highest activity among all of the studied catalysts, on which the conversion of thiophene can reach 100% at 400℃.

We have prepared copper electrodes by the hierarchical micropore hydrogen template method. By changing the plating current density and plating time, we can effectively control the size and distribution of the micropores. In addition, we altered the surface chemical composition to obtain electrodes with different wettability. The production and behavior of bubbles on the electrodes with different microstructures and wettability during the process of water electrolysis was investigated. The experimental results indicated that, compared with the hydrophilic porous electrode, the bubbles were able to pin onto the hydrophobic electrode more easily, and they tended to coalesce to form a stable gas film. The effect of the porous structure on the behavior of bubbles was more significant for hydrophilic electrodes than hydrophobic electrodes. The electrodes with hierarchical microporous structures preferred to produce more bubbles than those without microporous structures. The production rate of bubbles on the electrodes with hierarchical microporous structure was faster than that on the electrodes without. Furthermore, porous hydrophilic electrodes with large pore sizes could generate bubbles faster and pin smaller bubbles than electrodes with small pore sizes. We believe that these results can provide theoretical proof for the design of the electrodes with attached micro-bubbles to reduce drag resistance.

Effects of electric field and surface charge on the interfacial thermal resistance between water and solid are discussed by using nonequilibrium molecular dynamics simulation. The results reveal that the electric filed decreases the water-solid interfacial thermal resistance when it is perpendicular to the interface. However, it shows negligible effects on the thermal resistance when parallel to the interface. Both positively and negatively charged surfaces decrease the interfacial thermal resistance. The relation between the interfacial thermal resistance and the surface charge density or electric field strength follows the quadratic function. The study demonstrates that applying external electric field or surface charge is an effective method to manipulate the interfacial thermal resistance.

Two star-shaped molecules consisting of a 1,3,5-triazine core with peripheral tetraphenylethylene moieties, 2,4,6-tris(4-(1,2,2-triphenylvinyl)phenyl)-1,3,5-triazine (TTPE-Tr) and 2,4,6-tris(4-(1,2,2- triphenylvinyl)- [1,1-biphenyl]-4-yl)-1,3,5-triazine (TTPE-Ph-Tr), have been synthesized. These compounds were characterized by nuclear magnetic resonance spectroscopy (NMR), matrix assisted laser desorption/ionization-mass spectrometry (MALDI-MS) and elemental analysis. Both compounds exhibited aggregation-induced emission enhancement (AIEE) properties during addition of water to their tetrahydrofuran (THF) solutions. Results from UV-Vis spectroscopy, photoluminescence (PL) spectroscopy, and scanning electron microscopy (SEM) demonstrated that the restricted intra-molecular bond rotation (RIR) reduced non-radiative transitions in these compounds in the aggregated state, resulting in the fluorescence quantum yields (Φ_F) increase. TTPE-Tr was also found to display mechanofluorochromic behavior. This compound, a blue-green powder (Φ_F=24.4%, λ_em=508 nm), exhibited relatively weak yellow/green emission (Φ_F=14.7%, λ_em=517 nm) upon grinding. The phase transition process responsible for this mechanochromism was confirmed by PL spectroscopy, X-ray diffraction (XRD) and time-resolved fluorescence spectroscopy. Thermal analysis of TTPE-Tr and TTPE-Ph-Tr showed that these compounds possess excellent thermal stability, with decomposition temperatures of 464 and 385℃, respectively.

The fluorescence and Raman spectroscopic characteristics of the photo-induced electron transfer of Coumarin 343 (C343) dye-sensitized TiO₂ nanoparticles have been investigated. The results indicate that the red-shift of the absorption spectrum peaks and the fluorescence spectrum maxima can be attributed to the photo-induced electron transfer from the excited state of the absorbed C343 dye molecules and the charge transfer complex (C343/TiO₂) to the conduction band manifold of the TiO₂ nanoparticles. Back electron transfer of the system was investigated by time resolved fluorescence spectroscopy and takes place in around τ₁=31 ps. Raman spectroscopy of the C343 dye-sensitized TiO₂ nanoparticles reveals that the carbon bond stretching vibrations and ring breathing motions of the absorbed C343 dye molecules at the interface significantly contribute to the ultrafast interface photoinduced electron transfer.

Highly doped CuO/SiO₂ composite aerogels were prepared via a propylene oxide pre-reaction method with acetonitrile as solvent. In a typical synthesis process, tetramethoxysilane (TMOS), acetonitrile, deionized water, and propylene oxide were mixed together for pre-reaction. The solutions were then mixed with a CuCl2 acetonitrile-water solution, with added propylene oxide. The mixed solutions were transformed to the wet gels after being kept in the oven for 0.5 h at 35℃. The dark monolithic CuO/SiO₂ composite aerogels were obtained after drying with supercritical CO₂ and following thermal treatment. The density, specific surface area, average doping concentration, and compression modulus of the final aerogel samples were about 180 mg·cm^-3, 625 m²·g^-1, 19.91%± 2.42% (Cu:Si molar ratio), and 1.639 MPa, respectively. The aerogels, which were ideal materials for backlight targets, featured od formability and uniform dispersion. The gelation mechanism was also discussed by comparing our typical synthetic process with reference experiments. The results demonstrated that the reaction rates of the two precursors were balanced by changing the solvent and using the propylene oxide pre-reaction method, which realized the co-gelation. In addition, the method may inspire new synthetic ideas for preparation of other metal-oxide/silica composite aerogels.