Ternary hybrid TiO₂-SiO₂-polyoxometalates (POMs) synthesized by stepped sol-gel method exhibit remarkable efficiency in photodegrading the industrial dye Rhodamine B. Time resolved microwave conductivity (TRMC) and diffuse reflection spectrophotometry (DRS) were used to investigate excess charge-carrier lifetimes and the band gap of the ternary hybrid TiO₂-SiO₂-POM catalysts. The binding of TiO₂ and SiO₂ reinforces absorbance across the visible spectra and the combination of TiO₂ and POMs improves the stability of h⁺-e^- pairs, which are the active sites of the reaction. In the ternary hybrid system, the synergistic effect amongst the three components contributes to better photocatalytic ability under visible light illumination when compared with either monomer TiO₂ or POMs.

Protein folding is considered one of the most important topics in structural biology. An in-depth understanding of the folding-function relationship is one of the most important subjects for biologists, and is of interest to scientific researchers in other disciplines. The folding of proteins is often completed within the order of milliseconds to seconds, whereas the underlying atomistic details corresponding to structural alterations and intermolecular interactions often occur on the nanosecond or even smaller timescales. Accordingly, the unambiguous description of complicated folding behaviors remains inaccessible to routine experimental and theoretically-calculated resolutions. In this paper, we reviewthe problems that exist in recent experimental and theoretical studies examining the protein folding mechanism. The Trp-cage is a fast-folding mini-protein containing merely 20 amino acid residues, but adopts a well-packed hydrophobic core and tertiary contacts. Herein, we use the Trp-cage as an example and summarize the experimental and theoretical research carried out on the Trp-cage formation and its folding mechanism. The presentation primarily focuses on three aspects: (1) the folding temperature; (2) the folding initiation and proposed folding mechanisms; and (3) the role of key residues and its driving force for the folding of the Trp-cage mini-protein. Finally, we provide some suggestions on how to effectively simplify the complicated interaction networks of the Trp-cage mini-protein and decrease the complexity of the folding mechanism. This helps us to clarify the respective and cooperative contributions of residues involved in the formation of the Trp-cage and its folding dynamics, as well as provide useful insights for folding studies and more efficient rational peptide design.

Dye-sensitized solar cell (DSC), a new type of solar cell, have attracted widespread attention since they were first reported. The internal contact interfaces of DSC, especially TiO₂/dye/electrolyte interfaces, have always been a focus of research in this field. The adsorption of photosensitizers, and the injection, transport, and recombination of photoelectrons, which occur at the interface, have a significant effect on the DSC performance. Modification of the TiO₂/dye/electrolyte interface of DSC can effectively reduce dye aggregation, surpress electronic recombination, enhance electronic injection efficiency, and improve the transport rate, so it improves the photovoltaic performance and stability of the DSC. Modification can also affect the position of TiO₂ conduction band, the adsorption behavior of the dye, and other parameters. In this article, researches on the methods and mechanism of TiO₂/dye/electrolyte interface modification are reviewed. These include modification of TiO₂ photoanodes by various methods, the introduction of co-adsorbents into the dye bath, the co-sensitization by different dyes, and the use of electrolyte additives with different functional mechanisms in the electrolyte. Finally, problems existed in application of these modification methods and future development directions are discussed.

Recently, polymeric semiconductor graphitic carbon nitride (g-C₃N₄) has been widely used in fields related to energy and material science, because of its unique electronic structure and excellent chemical inertness. For example, it can function as a metal-free catalyst or as a catalyst support for organic synthesis, photocatalytic water splitting, oxygen reduction reactions, and loading of Au, Pd, Ag, and Pt nanoparticles. In addition, it can also serve as a porous covalent organic framework for the absorption of H₂ and CO₂ gases, or as a hard template for the generation of metal (oxy)nitrides. In this review, some recent advances in g-C₃N₄ synthesis and applications are presented. The prospects for the development of g-C₃N₄ in energy-and environment-related fields are also discussed.

Three atropisomeric tetrasaccharide-substituted zinc porphyrins (αβαβ-Zn-A, ααββ-Zn-A and αααβ-Zn-A) and one monosaccharide-substituted zinc porphyrin (Zn-B) were synthesized. We explored the interactions of these zinc porphyrins with a set of amino acid methyl esters (L/D-LeuOMe, L/ D-ThrOMe, L/D-ValOMe, and L/D-PheOMe)using visible titration and circular dichroism (CD) spectroscopy. We observed that all of them bind to L-amino acid methyl esters more closely than to those with D-configuration. In particular, ααββ-Zn-A gives a high enantioselectivity, K_L/K_D of 4.75, and could be used for chiral recognition of amino acid methyl esters. The binding constants of the three Zn-A compounds with methyl amino acid methyl esters are in the same order, i.e., K^θ(LeuOMe) > K^θ(ValOMe) > K^θ(ThrOMe) > K^θ(PheOMe), but the order of the binding constants for K^θ(PheOMe) > K^θ(LeuOMe) > K^θ(ValOMe) > K^θ(ThrOMe). In addition, we used imidazole as a probe to study the effects of achiral molecules on the conformations of the glycoconjugated porphyrins. The experimental results show that binding with imidazole causes adjustments in the conformations of the Zn-A compounds. The binding constants of the Zn-A compounds with imidazole and with methyl amino acid methyl esters are in the same order: K^θ(ααββ-Zn-A) > K^θ(αβαβ-Zn-A) > K^θ(αααβ-Zn-A).

The photodissociation dynamics of carbonyl sulfide (OCS) in helium droplets was studied using a velocity-map-imaging technique. The CO fragments were detected by (2+1)-resonance-enhanced multiphoton ionization. It was found that in the helium droplet environment, rotational cooling is much more efficient than vibrational cooling. The velocity map images for both CO (v=0) and CO (v=1) exhibit nearly isotropic angular distributions. The kinetic energy distributions show that most of the translational energies are relaxed in the finite-sized superfluid helium system. However, the average translational energies of the CO (v=1) images are higher than those of the CO (v=0) images. The relevant mechanism is briefly discussed.

Geometric and energetic criteria have been used to analyze the hydrogen bonding statistics and dynamics of aqueous solutions of dimethylsulfoxide (DMSO) of different concentrations using molecular dynamics simulation. These two hydrogen bonding criteria both reproduced the changes of the hydrogen bonding properties of the solutions with increasing concentration. Comparison of the results obtained using the two criteria revealed that the geometric criterion cannot exclude pairs that have weak pair interaction energy. As a result, the number of hydrogen bonds determined by the geometric criterion is larger than that by the energetic criterion. The energetic criterion has less ability to distinguish pairs that have improper relative orientation compared with the geometric criterion. However, the number of deficient hydrogen bonds determined by the energetic criterion is smaller than that by the geometric one. This deficiency of the energetic criterion results in longer hydrogen bonding lifetime than that of the geometric criterion. Thus, an extended criterion involving both geometric and energetic conditions is recommended for hydrogen bonding analysis.

The surface energies and surface relaxation of Pt(100), (110), and (111) surfaces, as well as the hydrogen adsorption behavior on three Pt surfaces and M-Pt(111) (M=Al, Fe, Co, Ni, Cu, Pd) bimetallic surfaces with a coverage of 0.25 ML were calculated by density functional theory (DFT). The most favorable adsorption sites, adsorption energies, and relaxation during adsorption were obtained. The hydrogen local density of states before and after the adsorption, the positions of the d-band center of different bimetallic surfaces with respect to the Fermi level were analyzed and further related to hydrogen adsorption energies. The calculations showed that the easiest adsorption sites of hydrogen on Pt(100), Pt (110), and Pt(111) are, in order, the bridge site, the short bridge site, and the fcc hollow site. The Pt(111) surface has the lowest surface energy among the three Pt surfaces and the Pt(111) surface is the most stable structure. However, the fcc hollow site is the most stable adsorption site for different M-Pt(111) bimetallic surfaces. The Ni-Pt bimetallic surface showed the lowest hydrogen adsorption energy among the M-Pt(111) bimetallic surfaces. The Co-Pt bimetallic surface showed the next lowest hydrogen adsorption energy, indicating that hydrogen adsorption on Ni-Pt and Co-Pt bimetallic surfaces is more stable. In addition, the first layer and the second layer have an expanding tendency with some degree after hydrogen adsorption on Ni-Pt, Co-Pt, and Fe-Pt bimetallic surfaces. The addition of a 3d metal surface layer on Pt(111) was found to move the d-band center closer to the Fermi level when compared with the bulk Pt metal, and increases the hydrogen adsorption ability by means of the density of state analysis of the bimetallic surfaces model. This reveals that 3d-Pt bimetallic surfaces are likely to have better dehydrogenation activity than Pt.

By applying the first-principles methods based on density functional theory and the slab model, we have studied the non-dissociative and dissociated adsorptions of a dodecylthiol (C₁₂H₂₅SH) molecule on Au(111) surface. Based on the calculated results, the fate of the H atom has been analyzed, and the longchain adsorption and short-chain adsorption have been compared. We have performed structure optimizations for a series of initial structures with the S atom located on different sites with different tilt angles. This structure optimizations gave two surface structures before and after the dissociation of S―H; the standing-up and lying-down adsorption structures. Our calculations indicate that the C₁₂H₂₅SH molecule prefers to stay on the top site, the corresponding adsorption energies are 0.35-0.38 eV. The dissociated C12H25S group prefers to adsorb on the bri-fcc site, with adsorption energies of 2.01-2.09 eV. We have compared the non-dissociative C₁₂H₂₅SH/Au(111) and dissociated C₁₂H₂₅S/Au(111) with the H atom adsorbing onto Au and desorbing as H₂, and found that the non-dissociative adsorption is more stable. The formation energy and the electronic structure showed that the non-dissociative adsorption belongs to the weak chemisorption, whereas the interaction between the S atom and Au surface becomes much stronger following cleavage of the S―H. A comparison of the adsorption of long-chain thiols on Au(111) surface with that of the short-chain thiols, indicates that the adsorption energies of the long-chain thiols are slightly larger, and the distances between the S atomand the surface Au atoms are slightly shorter.

The reaction mechanismof furan formation during decarbonylation of furfural on the Pt(111) plane was investigated by density functional theory generalized gradient approximation calculations with the slab model. The adsorption energy of furfural was calculated to determine preferred adsorption sites on the Pt(111) plane. The revealed possible mechanisms for the decarbonylation of furfural on the Pt(111) plane were studied. The results showed that a furfural molecule loses 0.765 electrons after adsorption on the Pt(111) surface. The d orbitals of the metal surface interact strongly with the π bonds of the furfural ring. This reduced the aromaticity of the furfural ring and the Catoms showed characteristics consistent with sp³ hybridization. The molecular plane of the adsorbate was distorted, and corresponding changes of bond lengths were found. The C―H(O) bonds and―CHO of furfural tilted away from the Pt surface. The calculations showthat furan was a possible product of the decarbonylation reaction. We then searched the transition states (TSs) and reaction potential energy surfaces with the linear and quadratic synchronous transit (LST/QST) complete search. By comparing energy barriers, we obtained the optimal path, which involved furfural forming an acyl intermediate by loss of the Hatom from the branched chain rather than direct decarburization. Furan was then formed by decarburization and hydrogenation of the acyl intermediate. The calculated barrier for the rate-determining step(C₄H₃O)CO^*+^*→C₄H₃O^*+ CO^* (^* is adsorption site) is 127.65 kJ·mol^-1.

2,4-Dichlorophenoxy acetic acid (2,4-D) is a herbicide and plant growth regulator that is widely applied inagriculture.Many chemical reactions takeplace inthemetabolismof 2,4-D. Herein, the hydrolysis reaction mechanismin 2,4-D metabolismwill be presented. In this study, a density functional theory approach, B3LYP, was employed toinvestigatethehydrolysis reaction mechanismalong three different paths. The computed results indicate that: (Ⅰ) there are two models of the hydrolysis reaction of 2,4-D. The dissociation mechanismof C(1)―O and C―Cl involve hydrogen transfer and Cl substitution, respectively. (Ⅱ) The energy barrier of C―Cl dissociation was lower and the dissociation showed advantageous dynamics. Two of the reaction paths that initiate the dissociation of C―Cl were primary reactions. The dissociation of C(1)―O was the last step in the primary reactions and had a higher energy barrier. In metabolism, the different intermediates have different concentrations, and this impacts on the reaction rate. (Ⅲ) In addition, it was necessary to consider the solvent effect to investigate the hydrolysis reaction. To characterize the solvent effect, the conductor-like polarizable continuum model (CPCM) was used to simulate the hydrolysis reaction with respect to the bond length and energy barrier.

Molecular dynamics (MD) simulations have been widely used for molecular systems; however, it is difficult to simulate nanosized devices because of limited computational capacity. Recently, we developed ultra-large MD simulation software, NanoMD. Here, we use this software to investigate a high speed rotatable nanodevice via the atomistic model of a nanogear. The stress distribution and failure mechanism of the nanodevice under high speed rotation is confirmed through dislocation defect analysis. The device strength is measured by focusing on the ultimate elastic rotation speed. There is an obvious size effect that limits the rotation speed of the nanodevice. The limiting speed increases with decreasing the diameter of the nanodevice. With shrinking the shaft diameter, it increases firstly, followed by a decrease.

The radicals generated fromreactions of 2'-deoxyadenosine-5'-monophosphate (dAMP) with an HO· radical were studied by the reliable B3LYP/DZP++ method. The results show that the initial primary products are the radicals of HO· addition at the C8 and C4 sites of dAMP and those of dehydrogenation from the NH₂ moiety of dAMP. Moreover, the initial radicals of the C4 site adducts of HO· tend thermodynamically to take place dehydration reactions that yields strong oxidizing, H-abstraction radicals fromthe NH₂ group of dAMP. The electrostatic repeller interaction between the dAMP molecule and HO· results in HO· addition radicals of the C2 atomof dAMP to be a by-product, even if they are relative stable species. These theoretical results agree well with available experimental observations and give proper explanations for some experimental results.

Determining highly active epitopes of the cytotoxic T lymphocyte (CTL) is essential for the computational design of peptide vaccines for tumors. In this study, we characterized each residue in the restricted CTL epitopes using 531 physicochemical properties. We selected 18 descriptors with clear meanings from 531×9 descriptors for each peptide of length nine using the binary matrix shuffling filter and worst descriptor elimination multi-round methods. Most of the 18 selected descriptors were the hydrophobic and steric properties of the residues. Among the 18 descriptors, 10 descriptors were related to the second, fourth, and ninth residues, which is consistent with the known facts. We then constructed a support-vectorregression-based quantitative sequence activity model (QSAM) using 18 selected descriptors. The values of the accuracies of fitting (R²), leave-one-out cross validation (Q_cv²), and extra-sample prediction (Q_ext², RMSE_ext) were 0.957, 0.708, 0.818, and 0.366, respectively. These results, which were tested on HLAA^* 0201 data, showed that our QSAM was superior to those reported in the literature. Finally, we predicted the activities of peptides of all possible combinations of the nine residues. Several peptides were found with higher affinity activities than those of previously reported epitopes. Our study improves the understanding of the relationship between the compositional residues and the affinity activity of the peptide, which provides a valuable guideline for the design of highly active peptide vaccines. Our predicted high affinity peptides are potential candidates for further experimental verification.

It has been reported that applying a certain external anodic potential over un-doped (α-Fe₂O₃) and Ti-doped α-Fe₂O₃ (Ti-Fe₂O₃) electrodes can improve the photocurrent or the photoelectrochemical oxidation rate of water. However, it is assumed in the literature that the potential drops completely across the side of the solid semiconductor (band edge pinning), and the influence of the potential on the interfacial charge-transfer rate constant is rarely reported. In this article, the impact of the applied potential on the interfacial charge-transfer rate constant during photoelectrochemical oxidation of water over the two electrodes was investigated by electrochemical impedance spectroscopy. The results showed that by increasing the applied anodic potential, the interfacial charge-transfer rate constants for both electrodes were increased. The smaller increase in the magnitude of the rate constant than determined by theory indicates that not all of the applied potential drops across the Helmholtz layer, but takes place in both the space charge and Helmholtz layers simultaneously (Fermi level pinning). The results of the surface-state capacitance measurements suggested that the photo-generated charge can be accumulated in the surface states, resulting in the re-distribution of the potential at the interface and an improvement in the rate constant. Under the same applied potential, the higher the light intensity is, the more the photogenerated holes accumulated in the surface states. This causes an increase in the potential drop across the Helmholtz layer and consequently increases the charge-transfer rate constant. Compared with the α-Fe₂O₃, the improvement of the charge-transfer rate constant by the anodic potential is more obvious.

Zinc-air battery is a high-power electrochemical system. Experimental data indicate that material usage decreases significantly with increasing applied current density. A one-dimensional mathematical model was established to simulate the discharge process of a high-power zinc electrode working under high current density conditions. Variable distributions within the electrode such as ionic concentrations, transfer current density, electrode porosity, and volume fraction of solid zinc oxide were predicted based on numerical solutions. The results demonstrate that the limitation of the mass transfer process by precipitation of solid zinc oxide is the main factor causing electrode failure. The precipitation time of solid zinc oxide and its concentrated distribution area have significant impacts on the electrode performance. The limitation of the mass transfer process is greatly aggravated if the volume fraction of zinc oxide exceeds specific values within a small range, approximately 30%-35%. The optimal designs of zinc electrodes were discussed. The numerical results indicate that high-power electrodes with higher ionic conductivities and porosities behave better. However, the most important requirement is to maintain a relatively high concentration of hydroxyl ions. For enclosed electrodes, infusion is an effective method, whereas an ideal design would consist of an open system with a circulating electrolyte, such as fluidized bed electrolyte.

To increase the specific surface area of ZnOnanosheets, a sulfuration and oxidization treatment was introduced. First, ZnO nanosheets were grown by the hydrothermal method at a low temperature on the conductive side of the fluorine-doped tin oxide (FTO) conductive glass. The same method was then used to obtain ZnS nanosheets by dipping the FTO with ZnO nanosheets into the precursor of the thioacetamide aqueous solution. In the end, ZnO nanosheets were gained again by sintering ZnS nanosheets at a high temperature in an air atmosphere. The effects of the treatment on ZnO nanosheets were studied with respect to morphology, structure, specific surface area, and pore size distributions. The results showed that the specific surface area of ZnO nanosheets can be doubled after the sulfuration and oxidization treatment. The samples were also introduced into the photoelectrode of dye-sensitized solar cells (DSSCs) and their dye-loading, current density-voltage (J-V), and the monochromatic incident photon-to-electron conversion efficiency (IPCE) were characterized and compared. The results showed that both the dye-loading and IPCE were increased via the sulfuration and oxidization treatment. Above all, the energy conversion efficiency of DSSCs was found to increase by 33%.

Activated hierarchically porous carbon (aHPC) was fabricated by calcination, etching and KOH activation using phenol-formaldehyde resin (PF) as the carbon precursor and nano-CaCO₃ dispersion as the double pore-forming agent. On this basis, the aHPC/2,5-dimercapto-1,3,4-thiadiazole (DMcT) composite was prepared through a solution immersion method using aHPC as the substrate, and poly(3,4-ethylenedioxythiophene)-poly(4-styrenesulfonate) (PEDOT-PSS) was coated subsequently onto the surface of aHPC/DMcT by in situ oxidative polymerization to prepare the aHPC/DMcT/PEDOT-PSS composite. The structure, morphology, and electrochemical properties of the composite were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and electrochemical measurements. The results showed that the amount of the functional groups in aHPC pores increased after HPC was activated by KOH, resulting in an enhancement (52%) of the adsorption of DMcT. Moreover, almost all of the DMcT was absorbed into the aHPC pores. It was found that the initial discharge capacity of the aHPC/DMcT composite was 236 mAh·g^-1 and its specific capacity remained at 65 mAh·g^-1 after 20 cycles. For comparison, with a surface coated with a layer of PEDOT-PSS conductive film, the initial discharge capacity of the aHPC/DMcT/PEDOT-PSS composite was up to 280 mAh·g^-1 and it remained at 138 mAh·g^-1 after 20 cycles (49.1% capacity retention).

Na₂MnPO₄F/C composites were synthesized by wet ball milling and in situ pyrolytic carbon coating. Stearic acid, citric acid, poly(ethylene glycol) 6000, and β-cyclodextrin were used as carbon sources in the synthesis process. The structures, morphologies, and electrochemical performances of the as-synthesized Na₂MnPO₄F/C composites were further investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller surface area analysis, and galvanostatic chargedischarge tests. Distinct differences were observed in the morphologies and sizes of the Na₂MnPO₄F/C particles obtained from different carbon sources, and this significantly affected their electrochemical performances. It was found that the primary particle size of the Na₂MnPO₄F/C material is a key factor in the electrochemical performance. The sample synthesized using citric acid as the carbon source had a micro-nano structure, with the smallest primary particle size of 10-40 nm, and displayed the best electrochemical properties. It delivered an initial discharge capacity of 80 mAh·g^-1 under a current density of 5 mA·g^-1 in the voltage range of 1.5-4.8 V, and displayed od cycling performance.

We fabricated activated carbon (AC)-based supercapacitors encased in flexible packaging using a novel organic electrolyte, triethylmethylammonium tetrafluoroborate/acetonitrile+propylene carbonate (MeEt₃NBF₄/(AN+PC)), and two conventional organic electrolytes, tetraethylammonium tetrafluoroborate/acetonitrile (Et₄NBF₄/AN) and tetraethylammonium tetrafluoroborate/propylene carbonate (Et₄NBF₄/PC). Cyclic voltammetry and electrochemical impedance spectroscopy measurements in various voltage windows were conducted. In addition, a comprehensive comparison of these three electrolytes was conducted via data obtained from cyclic voltammetry, electrochemical impedance spectroscopy, galvanostatic charge-discharge, leakage current, self-discharge, cyclic life, and coulombic efficiency within the 0-3 V voltage window. The results indicate that MeEt₃NBF₄/(AN+PC) combining the advantages of AN and PC exhibits excellent performance.

Three novel dimeric cholesteryl-based low-molecular-mass gelators (LMMGs), which have the structure A(LS)₂, were designed and synthesized. In the structures, 1,3-diaminopropane is a linker (L), A is a benzene ring, and S is cholesteryl. According to the positions of the substituents on the benzene ring, the as-prepared compounds are denoted by 1 (o-position), 2 (m-position), and 3 (p-position), respectively. Their gelation properties were evaluated in 30 solvents. It was revealed that the relative positions of the two cholesteryl moieties on the benzene ring play a crucial role in the gelation behaviors of the compounds. In terms of the number of solvents gelled by the tested compounds, compound 3 is a more versatile gelator than compounds 1 and 2; compounds 2 and 3 can form five gels at room temperature. Furthermore, the compound 2/xylene gel is transparent and flexible, and forms a supramolecular filmin the wet state. Fouriertransform infrared (FTIR) spectroscopy and ¹H nuclear magnetic resonance (¹H NMR) spectroscopy studies demonstrated that intermolecular hydrogen bonding and π-π stacking among the molecules of the gelators play important roles in the gelation process. X-ray diffraction (XRD) analysis showed that the aggregate of compound 1 from its benzene gel adopts a hexa nal packing mode as the elementary structure of the gel networks.

We studied the impact of the addition of Gum Arabic on the dilational properties of Gemini surfactants. The investigation found that the addition of 1% (w) Gum Arabic in the Gemini surfactants solutions caused a decrease in the interfacial tension, but the addition of 1% (w) Gum Arabic resulted in the dilational modulus increasing significantly. The explanation to this observation is that the electrostatic interaction of the Gum Arabic/surfactant complex increased and the dilational modulus increased. A possible schematic diagrams of the adsorbed Gemini molecules with Gum Arabic at the decane/water interface is proposed.

The adsorption of Co(Ⅱ) and Ni(Ⅱ) on crushed Beishan granite (BS03, 600 m) was studied by a batch experimental method. The distribution coefficient (K_d) was found to vary as a function of the pH, ionic strength, and the initial concentrations of Co(Ⅱ) and Ni(Ⅱ). In the low pH range, the K_d values of Co(Ⅱ) and Ni(Ⅱ) decreased significantly as the ionic strength increased, whereas the effect of the ionic strength was weak in the high pH range. The adsorption of Co(Ⅱ) and Ni(Ⅱ) on granite was quantitatively interpreted by a model with one cation exchange reaction and two inner-sphere surface complexation reactions. A linear free energy relationship (LFER) between the equilibrium constants (K) of the surface complexation reactions and the hydrolysis stability constants of the divalent transition metals (^OHK) was established. Predictions based on the LFER are in od agreement with the experimental results for the adsorption of Pb(Ⅱ) and Cu(Ⅱ) on granite.

The heterogeneous oxidation of carbonyl sulfide (COS) on hematite pre-adsorbed with ammonia and methylamine, trimethylamine, triethylamine, phenylamine, pyridine, and pyrrole was investigated using in situ diffuse-reflectance infrared Fourier-transform spectroscopy (DRIFTS) at room temperature. The products and kinetics of the heterogeneous reaction were investigated. The results showed that adsorbed COS could be oxidized on the surface of hematite pre-adsorbed with these basic substances, forming gaseous carbon dioxide (CO₂), surface bicarbonate (HCO₃^-), surface carbonate (CO₃^2-), and surface SO₄^2-. Ammonia and amines pre-adsorbed on hematite significantly enhanced the reactivity of COS. Hematite with pre-adsorbed methylamine exhibited the highest reactivity, about 4.5 times higher than that of pure hematite, whereas the effects of phenylamine and pyrrole were not obvious. The reaction rates with the basic substances were in the order of methylamine>trimethylamine>ammonia>triethylamine>pyridine> pyrrole> phenylamine≈pure hematite. The basic substances changed the reaction order from first to second. Coverage by the basic substances and surface water also played important roles in the heterogeneous reaction of COS. These experimental results indicated that surface oxygen species (M―O^-) were the key factor contributing to oxidizing activities in the presence of basic substances. The heterogeneous oxidation mechanism of COS on hematite with pre-adsorbed basic substances is discussed on the basis of the experimental results.

Nanosheet ZSM-5 zeolites with different SiO₂/Al₂O₃ molar ratios have been hydrothermally synthesized by an organic surfactant with a diquaternary ammoniumgroup. The samples were characterized by X-ray diffraction (XRD), N₂ adsorption-desorption, X-ray fluorescence spectroscopy (XRF), scanning electron microscopy (SEM) and ²⁷Al magic angle spinning nuclear magnetic resonance (²⁷Al MAS-NMR) techniques. The synthesis conditions of the nanosheets ZSM-5 were studied, including the synthesis factors such as crystallization temperature and time, the amount of structure-directing agent (SDA) and alkalinity. The results showed that shorter crystallization times were required when synthesis was conducted at higher crystallization temperatures, higher SiO₂/Al₂O₃ ratios, larger amounts of structure-directing agent were used, and higher SiO₂/Al₂O₃ ratios. The morphology, BET and mesopore volume changed with increasing SiO₂/Al₂O₃.

Three kinds of mononucleonic metal complexes of L¹Cu, L¹Co, and L¹Mn (L¹=N,N'-bis-(2-hydroxyethyl)-malondiamide), and three kinds of binucleonic metal complexes of L²Cu, L²Co, and L²Mn (L²= N,N'-bis{2-(2-hydroxyethylamino)ethyl}-malondiamide) were prepared. These complexes exhibited od catalytic performance for the selective oxidation of 4-methoxymandelic acid (4-MMA) by H₂O₂ in buffer solution, with >96% selectivity to anisaldehyde (AAD) and a small percentage to 4-methoxybenzoic acid (4-MBA). However, the reaction rates were quite different for these catalytic systems, in which the copper complex was the best candidate as the catalyst for the oxidation of 4-MMA. The binucleonic complexes displayed obviously better catalytic performance than the mononucleonic complexes. The effect of the applied buffers (tartaric acid (TA), H₃O₄, HAc) on the catalytic performance in terms of activities and selectivities for the oxidation of 4-MMA by H₂O₂ were investigated. The reaction kinetics of 4-MMA oxidation catalyzed by six complexes was studied in detail. The apparent first-order rate constants (k_obs) were obtained in the pH range of 2.5 to 4.5. The pHeffect on the catalytic oxidation was discussed in this paper.

Surface promoters-modified Cu/ZnO/Al₂O₃ (CZA) catalysts were prepared by a coprecipitationpost impregnation method and evaluated in methanol synthesis fromsyngas. The effects of Zr, Ba, and Mn as promoters, the reaction temperature and run time over CZA and Zr-promoted CZA catalysts on catalytic performance were investigated, respectively. The catalysts were characterized by X-ray diffraction (XRD), N₂-sorption, reactive N₂O sorption, X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption of H₂ (H₂-TPD), scanning electron microscopy (SEM), and high-resolution transmittance electron microscopy (HR-TEM). The results showed that the space-time yield (STY) of methanol can be increased noticeably over the Zr-or Ba-promoted CZA catalyst before and after the heating treatment of the catalysts. The introduction of Mn as a promoter onto the CZA catalyst led to a decrease in the STY of methanol before heating treatment. The introduction of Zr as a promoter onto the CZA catalyst can decrease the temperature at which the STY of methanol reached the highest value and also improve the catalytic stability. A hydrogen molecule can be adsorbed and then activated over Cu⁰ and ZnO. The strong interaction between Cu⁰ and ZnO is favorable for improving the catalytic performance of the CZA catalyst. The decrease in catalytic performance after heating treatment of the CZA catalysts is attributed to a growth of Cu⁰ crystallites. Based on the results of catalytic performance and characterization, a possible "bidirectional but synchronous catalytic reaction course" in methanol synthesis from syngas over a CZA catalyst is proposed.

Aseries of luminescent glass composed of CaO-CaF₂-B₂O₃-SiO₂ doped with samariumoxide (CFBS: Sm) were prepared. The structure, infrared transmittance and fluorescent properties of the samples were investigated by X-ray diffraction (XRD), Fourier transforminfrared (FTIR) spectroscopy and photoluminescence (PL) measurements, respectively. The XRD patterns of the CFBS:S msamples showed that the glass matrix had a non-crystalline structure, while the FTIR spectra exhibited shifts of absorption wavelength sensitive to the structure and function of the samples. The PL spectra of the CFBS:Smglasses showed the characteristic emission of Sm³⁺ centered at 566, 603 and 650 nmunder 404 nmexcitation, and their luminescence color was red-orange (x=0.531, y=0.371). Furthermore, the intensity of emission and fluorescent lifetime of Sm³⁺ at 603 nm (⁴G_5/2) increased with the molar ratio of CaF₂ in the glass samples. The enhanced intensity of emission, fluorescent lifetime and quantumefficiency with increasing molar ratio of CaF₂ may result fromthe reduction of phonon energy in the CFBS:S mglass because some CaF₂ substitutes CaO in the glass matrix.

Zn₂GeO₄ nanoribbons were synthesized via a microwave-hydrothermal method. The effects of reaction factors, such as reaction temperature, amount of reactants and template, were investigated and optimized for the formation of Zn₂GeO₄ nanoribbons. The products were characterized by various techniques including field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). Photocatalytic activities of the synthesized Zn₂GeO₄ nanostructures were evaluated for the degradation of aqueous methyl orange. Experimental results indicated that Zn₂GeO₄ nanoribbons can be synthesized from Zn(CH₃COO)₂ and GeO₂ (molar ratio 2: 1) under microwave irradiation at 160℃ for 20 min. The nanoribbons have uniformsizes with widths of 100 nm and are tens of micrometers in length. Compared with conventional hydrothermal methods, Zn₂GeO₄ nanoribbons from microwave-hydrothermal synthesis have less native defects, lower PL spectra, 50.7% larger specific surface area, and 54.7% higher photocatalytic activity.