The number and distribution of trap states in nanoporous Ti O2 thin films effect on the electron transport and recombination,and then affect the dye-sensitized solar cell(DSSCs) performance.This paper study the trap state number in nanoporous films composed of 10,20,80 and 200 nm Ti O2 nanoparticles by means of three electrode system,based on the electrochemical impedance spectroscopy(EIS) and the cyclic voltammetry(CV).The results show that the content of trap states decreases with the increase of particle size.And X-ray photoelectron spectroscopy(XPS) characterization shows that the content of Ti3+ and oxygen vacancies in the porous films decrease with the increase of particle size.The research provides a description of microscopic mechanism for the effect of porous films with different sizes on cell photovoltaic performances.
A purification step after synthesis has become a standard procedure for many DNA nanostructures studies. We firstly applied anion exchange chromatography(AEC) to DNA nanocages purification. A 20 bp-edge DNA bipyramid and five DNA tetrahedra with different edge lengths including 13, 17, 20, 26 and 30 bp were purified effectively by AEC, which improved the purity of these nanostructures from 30%–65% up to 95%. And the yield of a dumbbell-like nanostructure which was constructed using AEC-purified DNA tetrahedra was more than 90%, but 11% for the unpurified group. Given the versatility of this method, AEC is promising for other DNA nanocages and other DNA nanostructures purification.
Living radical polymerization has attracted increasing attention due to its high efficiency and precision in synthesis of specific polymeric materials.This article summarizes recent progresses in organometallic mediated radical polymerization(OMRP),which is one of the most important LRP methods.Various organometallic complexes include titanium,vanadium,chromium,molybdenum,iron,osmium,cobalt,rhodium,palladium and copper mediating living radical polymerization.Applications of OMRP in photo-induced OMRP,synthesis of block- copolymers,combination with other LRPs,and terminal functionalization or modification of polymer chain are described.
It was essential to rapidly reactivate and restore the function of the inhibited acetylcholinesterase(AChE) in the treatment of nerve agents poisoning. However, the blood-brain barrier(BBB) restricts the rapid transport of reactivators from the blood into the brain in therapeutically relevant concentrations. In this study, human serum albumin nanoparticles(HSA NPs) were prepared via desolvent method; HI-6, the known reactivator with higher reactivating efficiency were bound to HSA NPs through electrostatic interaction; at last, on zebrafish BBB model and soman-intoxicated mice, the permeability on BBB and the reactivation on inhibited brain AChE of nanoparticulate oxime formulations were evaluated. All characterization data revealed that HSA NPs loaded with HI-6 had met the basic demand for nanodrug therapy. Compared with free HI-6, HSA NPs loaded HI-6 could cross the BBB and improve the reactivating rates two times, suggesting HSA NPs could carry HI-6 into CNS successfully. In brief, we improved and established a method to prepare the brain-targeted nanoparticles with small-size, low-toxicity and high-efficiency, the targeted drug based on this method could efficiently release and rapidly antagonize the nerve agents poisoning.
Semiconductor nanocrystals have attracted extensive attention in photoelectrical devices and biomedical applications over the past decades due to their plentiful band gaps and optical properties.Therefore,rational design and precise modulation of their optical properties are of great importance.This review briefly summarized our recent progress in controlled synthesis of semiconductor nanocrystals with different bandgaps,and the self-assembly of nanostructures with novel optical properties assembled using DNA and protein as templates.In the end,we summarized the novel optical properties and biomedical applications of the obtained semiconductor nanocrystallines and nanostructures.
Methionine can be oxidized to methionine sulfoxide, causing redox imbalance in vivo and inducing many diseases. Methionine sulfoxide reductases(Msrs) can reduce methionine sulfoxide to methionine, thus renovate protein structure and function, and prevent oxidative stress-relevant diseases. This review mainly includes the classification and evolution of Msrs, the protein structural feature and catalytic mechanism, and protein expression via genetic engineering. It summarizes recent development in Msrs and aging or Parkinson's disease or Alzheimer's disease, as well as our own results. The prospect of Msrs research is also discussed in this paper.
Fundamental research on ionic liquids has promoted their wide applications including catalysis,organic synthesis and materials,which provides new method for developing green catalysis processes.This article reviews some representative ionic liquid-based catalytic reactions,such as CO2 cycloaddition,alkylation,hydroformylation,transesterification,oxidation,CO2 hydrogenation,cross-polymerization and depolymerization,with the aiming of highlighting the roles of ionic liquids on reaction efficiency,the reduction of emissions and separation.Furthermore,the prospective to the development in this field is discussed.
It has become a research focus in the world that using consolidated bioprocessing to produce the second generation bioethanol(cellulosic ethanol).However,previous studies indicated that the non-complexed cellulase systems engineered in Saccharomyces cerevisiae did not work efficiently.During recent years,cell-surface assembly of complexed cellulase systems(cellulosomes) on S.cerevisiae has attracted continued interests,because of their greater abilities in cellulose hydrolysis than non-complexed cellulase systems.Up to now,the self-assembly and semi-self-assembly of celllulosomes using single scaffoldin or two scaffoldins have been achieved.The cellulosome-displayed yeast has been able to directly convert avicel to ethanol,but the productivity was still quite low because of some design flaws of cellulosome.In this paper,the methods for cellulosome assembly on yeast cell surface and their applications in cellulosic ethanol production are reviewed.Also,the prospects of this research field are given based on our analysis of the problems that still have not solved by the previous studies.
In 1960s, Rosenberg discovered the anticancer activity of cisplatin, and heralded a new era of anticancer drug research based on metallopharmaceuticals. During the past 40 years, carboplatin, nedaplatin, oxaliplatin, eptaplatin, lobaplatin and dicycloplatin have been successfully developed. Although some results were achieved for platinum anticancer drugs, some problems often limited their clinical use by severe toxic side-effects, as well as the intrinsic and acquired resistance possessed by various cancers. In order to solve these problems, new metal-based anticancer drugs were started to found. Based on the similarity of structural and chemical properties between platinum(II) and palladium(II) complexes, palladium(II) complexes as the potential antitumor drug have become an attractive field. This review summarized the current development of palladium(II) complexes as potential antitumor agents, and the structure-activity relationship were studied, which will be valuable for guiding the synthesis of new type palladium(II) anticancer drugs.
Electrocatalysts for the oxygen reduction and oxygen evolution reactions play a critical role in the performance of metal-air batteries. In this study, a phosphorus doped carbon nanotube(P-CNT) is facilely synthesized via a one-step process and in-situ solvothermal method. The electrocatalytic activity for the oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) of the catalyst was studied with the rotating ring-disk electrode(RRDE) technique. The doping of phosphorus can obviously improve the electrocatalytic activity of CNT towards both the ORR and OER. Four electron reduction pathway is dominant on P-CNT during the ORR process, which is comparable to the commercial Pt/C(20 wt%). The electrocatalytic activity of P-CNT towards the OER is superior to that of Pt/C(20 wt%). Moreover, the long-term stability of P-CNT outperforms that of Pt/C(20 wt%). The high electrocatalytic activity and long-term stability of P-CNT are attributed to P-doping in CNT and the strong coupling between phosphorus and carbon.
The mechanism of CuI/BtH catalyzed C–S coupling reaction of benzenethiol and 1-bromo-4- methoxybenzene to synthesize(4-methoxyphenyl)(phenyl)sulfane has been investigated by density functional theory(DFT). The geometries of reactants, intermediates, transition states, and products were optimized in both gaseous phase and solvent N,N-dimethyl formamide(DMF) at the B3LYP/6-31+G(d) level. The single point energies and zero point energy correction were calculated for the optimized configuration of each compound at B3LYP/6-311+ +G(d,p) level. Vibration analysis, energy calculation and IRC calculation proved the authenticities of the intermediates and the transition states. Atoms in molecules(AIM) and nature bond orbital(NBO) theories were used to discuss the bond nature and orbital interactions at the same of optimization calculation level. In CuI catalytic mechanism, there is one pathway, the rate-determining step activation energy of which is 180.49 kJ/mol in solution. In CuI/BtH catalytic mechanism, there are two possible pathways: IA is the optimal pathway and the activation energy of rate-determining step is 101.77 kJ/mol; the activation energy of rate-determining step in IB is 143.78 kJ/mol(sol). Since the ligand 1H-benzo[d][1,2,3]triazole(BTH) can reduce the activation energy of rate-determining step and the dissociation energy of catalyst, meanwhile, it is favorable for the separation of products and catalyst, which is in accordance with experimental results.
The monodisperse silica-coated manganese oxide nanoparticles(NPs) were synthesized via a thermal decomposition approach and were aminated through silanization. The amine-functionalized core-shell NPs enabled the covalent conjugation of organic hydrophilic PEG and folate(FA) onto their surfaces. The formed Mn3O4@SiO2-PEG-FA core-shell nanocomposites are water-dispersible, stable, and biocompatible. Furthermore, we demonstrate that Mn3O4@SiO2-PEG-FA NPs as a T1 contrast agent display effective targeting ability, and lower toxicity in vitro, enabling them to be developed as multimodel nanoplatform for long-term targeted imaging.
Visible-light-driven Ag@AgCl deposited Ag NPs on cubic AgCl was prepared via the reduction of precursor AgCl by glucose at room temperature, and it was characterized by X-ray diffraction(XRD) and field-emission scanning electron microscopy(FE-SEM). In situ characteristic thermal spectrum and accurate thermokinetic information of three luminous power regarding the photocatalysis of methyl orange were obtained by first employing a novel photoreaction-microcalorimetric system designed by our laboratory. Associated with dynamic information acquired by UV spectrum, and rationally combined the fore three mentioned with the feature of step-wise photodegradation of methyl orange, the photocatalytic mechanism was discussed. The results showed that the initial destruction of azo double band via rapidly endothermic reaction under visible light and followed by a exothermic stage of the oxidation of intermediate products which finally kept a constant exothermic rate for at least 5 h. The procedure of this photocatalysis was influenced by the comprehensive factors of luminous power, mass transfer and diffusion, and the generation rate of reactive oxygen species. The variation of heat effect were lagged as the decrease of luminous power, simultaneously the photodegradation rate slowed down, which took much longer to reach the maximum endothermic peak, exothermic peak, and completely degrade methyl orange.
As one kind of unusual catalytic materials in the industrial catalysis community,the bimetal materials have attracted considerable attentions due to the controlled composition,size and nanostruture of crystals and their promising reasonable controlled catalytic activity in the catalytic reaction.In recent years,the controlled preparation of different kinds of nanomaterials has achieved rapid progress,these nanomaterials with little size and controlled structures are very significant to improve the catalytic activity and study the catalytic mechanism.It is a challenge to design and develop more efficient bimetal catalytic materials with the help of modern nanotechnology.In this review,we discussed the bimetal nanomaterials catalytic activity in kinds of catalytic reaction,and the influence factors of the catalytic activity of these bimetallic nanomaterials in the recent catalytic research progress.Some new promising characterization and research methods were also discussed in the end of the review.
The particle size effect on partial hydrogenation of benzene to cyclohexene over Ru/ZrO2 catalysts is reported.Uniform Ru nanoparticles(NPs) with a tunable particle size from 2.4 to 5.4 nm were synthesized by a polyol reduction method and deposited on ZrO2.The catalysts were characterized by ultraviolet-visible absorption spectroscopy(UV-Vis),N2 physisorption,H2 chemisorption,temperature-programmed desorption of H2(H2-TPD),powder X-ray diffraction(XRD),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS).It was found that the type of polyol and the concentration of additive(sodium acetate trihydrate) imposed remarkable effect on the particle size of Ru.A distinct particle size effect occurred in partial hydrogenation of benzene.With the size of the Ru NPs increasing,the hydrogenation activity of benzene increased,and the initial selectivity(S0) to cyclohexene showed a volcanic-type variation tendency,which revealed that the optimal Ru size for obtaining the highest S0 is 4.4 nm.The Ru/ZrO2 catalyst reduced by 1,2-propanediol exhibited the highest S0(82%) and the yield of cyclohexene(39%).Based on the characterization results,the size effect of Ru on the activity and selectivity is discussed.
Ideal of green chemistry is the reaction of economy and production of environment-friendly green products.This requires that every atom in the raw materials would transfer into the production,no production is of waste and by-products,and no usage of the poisonous and harmful materials.Practice the concept of green chemistry,Research Institute of Petroleum Processing successfully developed the green caprolactam production technology,to construct 200 kt/a plant.The innovation technology includes:TS-1 zeolite integration with single-vessel continuous slurry bed for cyclohexanone ammoximation;silicalite-1 zeolite integration with moving bed for cyclohexanone oxime rearrangement,and amorphous Ni alloy integration with magnetically stabilized bed for purification of caprolactam.Based on the commercial application results,the caprolactam production plant investment decrease 70%,operation costs decrease 10%,atom utilization rate increases to 90% from 60%,and essentially waste-free,respectively.Green caprolactam production technology produces great economic and social benefits,practices green chemistry concepts,and be a successful example of green chemistry.
The investigation on the separation and recovery of ionic liquids from water would be of great importance in reducing environmental impact of ionic liquids, enhancing their utilization efficiency, decreasing their industrial cost and promoting their industrial application. In this review, we focused our attention on the research progress in the recovery of ionic liquids by using salt + ionic liquid aqueous two-phase systems, sugar + ionic liquid aqueous two-phase systems, polymer + ionic liquid aqueous two-phase systems, and carbon dioxide induced aqueous two-phase systems. The main influence factors on the recovery of the ionic liquids were analyzed, and advantages and disadvantages of different ionic liquid aqueous two-phase systems were evaluated. The development in the ionic liquid recovery was prospected and the challenges were stressed.
Nano-structured materials have played an important role in chemical process intensification with the development of chemical technology. Metal-organic frameworks(MOFs) built up from inorganic subunits and organic moieties have been recognized as a new family of nanoporous materials with potential applications in different fields including gas storage, separation, catalysis, sensing and drug delivery. In this paper, MOFs were adopted as an example to introduce how thermodynamics and computational chemistry can help to study the structure-property relationships and design of nano-structured materials.
Zn-Ni-Cu ferrites(ZNCF) and their poly(o-methoxyaniline) composites(ZNCF/POMA) were prepared by a chemical precipitation method and an in situ polymerization method, respectively. The structures, morphology, conductivity and magnetic properties of as-obtained samples were characterized by means of modern analyticaltechniques such as X-ray diffraction analysis(XRD), scanning electron microscope(SEM), transmission electron microscope(TEM), vibrating sample magnetometer(VSM), etc. The results showed that there were some interactions between the component in the ZNCF/POM composites. The magnetization of the composites decreased with increase of the poly(o-methoxyaniline) content, while the conductivity performed contrary. Hence, the electrical and magnetic properties of the composites can be modified by changing the content of the components. Compared tothe single component, the POMA/ZNCF compounds exhibited excellent absorbing propriety on electromagneticwave. The POMA/ZNCF compounds with ωZNCF of 20% had the minimum reflection loss of-27.32 dB in resonancefrequency of 11.61 GHz and an available bandwidth of 8.81 GHz, and it is a kind of absorbing materials with excellent application prospect.
This review summarized different kinds of inhibitors that affect the aggregation and fibrillation of amyloid proteins. The metal complexes were optimized as potential and effective inhibitors of amyloid proteins. Moreover, the interaction systems of amyloid proteins were also generalized in the aspect of thermodynamics studies.
