含氟聚乙烯锂离子电池隔膜的钛化改性

采用物理沉积技术对氟化聚乙烯隔膜进行钛化改性,并采用扫描电子显微镜和电化学分析方法,研究钛化改性对氟化聚乙烯隔膜的结构和性能的影响。结果表明,Ti涂覆在氟化聚乙烯隔膜上不仅保留了聚乙烯隔膜本身的特性,而且提高了其热收缩性能,安全性能也随之提高。扣式电池的检测数据结果显示,采用沉积时间为30 min的Ti改性氟化聚乙烯隔膜制作的扣式电池的库伦效率与未钛化的氟化聚乙烯隔膜制作的电池相比基本上是一致的,但其放电克容量保持率优于未钛化的氟化聚乙烯隔膜,且研究结果揭示沉积在聚乙烯隔膜表面的Ti层具有嵌入和脱出锂离子的能力。

Photocatalysis fundamentals and surface modification of TiO_2 nanomaterials

As a green and sustainable technology,heterogeneous photocatalysis using semiconductors has received much attention during the past decades because of its potential to address energy and environmental problems. Among various semiconductors,TiO2 has been regarded as the best and most widely investigated photocatalyst in the past 10 years. Based on the fundamentals of photocatalysis and surface chemistry of TiO2 nanomaterials,we herein summarize and discuss the achievements in the different surface modification strategies employed to date such as surface doping and sensitization,construction of surface heterojunctions,loading of nano-sized co-catalysts,increase in the accessible surface areas,and usage of surface F effects and exposure of highly reactive facets. Especially,the interesting synergistic effects of these different surface modification strategies deserve more attention in the near future. Studying these important advances in photocatalysis fundamentals,and surface chemistry and modification may offer new opportunities for designing highly efficient TiO2-based and non-TiO2-based photocatalysts for solar fuel production,environmental remediation,organic photosynthesis,and other related fields such as solar cell device fabrication,thermal catalysis,and separation and purification.

Recovery of Fe,V,and Ti in modified Ti-bearing blast furnace slag

A two-stage oxidation—alkali leaching—acid leaching method was proposed to recovery Fe,V,and Ti in modified Ti-bearing blast furnace slag.The optimal experiment conditions of iron extraction were one-stage oxidation time 40 s and holding time 8 min.The recovery rate of iron was 89.93%.The optimum experiment conditions of vanadium extraction were total oxidation time of 126 s,NaOH concentration of 4.0 mol/L,leaching temperature of 95℃,leaching time of 90 min,and the number of cycle was 4.The leaching rate of vanadium was 92.13%.The optimal experiment conditions of titanium extraction were HCl concentration of 4.5 mol/L,leaching temperature of 75℃,and leaching time of 90 min.The TiO_(2)content of synthetic rutile was 98.61%.

Heterogeneous interfacial engineering of Pd/TiO2 with controllable carbon content for improved direct synthesis efficiency of H2O2

Series of heterogeneous interfacial engineered TiO2(C-TiO2) with controllable carbon content were facilely synthesized by incipient-wet impregnation using glucose and subsequent thermal carbonization. The obtained C-TiO2 were used as catalytic supports to load Pd nanoparticles for H2 O2 direct synthesis from H2 and O2. The as-prepared samples were systematically studied by transmission electron microscopy(TEM), X-ray photoelectron spectroscopy(XPS), air isothermal microcalorimeter, temperature-programmed reduction of H2(H2-TPR), and so on. The catalytic results showed that H2 O2 productivity and H2O2 selectivity of Pd/C-TiO2 firstly rose with increasing carbon content and then declined. Pd/C-TiO2 catalyst with 1.89 wt% of carbon content showed the best catalytic performance that had 61.2% of selectivity and 2192 mmol H2O2/g Pd/h of productivity, which were significantly better than those of pristine Pd/TiO2(45.2% and 1827 mmol H2O2/g Pd/h). Various characterization results displayed that the carbon species were heterogeneously dispersed on TiO2 surface. Moreover, no obvious geometric transformation in supports and Pd nanoparticles were observed among different catalysts. The superficial hydrophobicity of Pd/C-TiO2 was gradually promoted with increasing carbon content, which led to the corresponding decrease in adsorption energy of H2O2 with catalysts. According to structure-performance relationship analyses, the heterogeneous interfacial engineering of carbon could maintain the interaction of Pd nanoparticles with TiO2 and simultaneously accelerate the H2O2 desorption. Both factors further determined the excellent H2O2 direct synthesis performance of Pd/C-TiO2.

Simultaneous formation of a C/N-TiO_2 hollow photocatalyst with efficient photocatalytic performance and recyclability

Herein,we report a unique approach towards the preparation of C-modified and N-doped TiO2 hollow spheres(C/N-TiO2).TEM,SEM,and XPS analyses were used to confirm that the carbon and nitrogen co-decorated TiO2 photocatalyst was formed.Carbon-decoration improves the visible-light absorption and speeds up the separation of the photo-generated electron-hole pairs.C/N-TiO2 not only narrows the band gap of TiO2,but also exhibits excellent photocatalytic activity for the degradation of tetracycline and tetracycline hydrochloride.In addition,the C/N-TiO2 photocatalyst shows excellent recyclability for water decontamination,making it a promising candidate to purify aquatic contaminants.

Surface Modification of Nanometer TiO_2 and Effect of Preparing TiO_2/P(St-co-DVB) Composites by Dispersion Polymerization

Surface modification of nanometer titanium dioxide particles and effect of preparing TiO2/P （St-co-DVB） composites by dispersion polymerization are described. To introduce vinyl group onto the surface of titanium dioxide particles, the titanium dioxide particles were surface-modified with a silicane coupling agent, methacryloylpropyltrimethoxysilicane. Polymer encapsulation in the presence of either modified-titanium dioxide particles or unmodified-titanium dioxide particles was carried out by dispersion polymerization of styrene, divinylbenzene in ethanol medium with polyvinylpyrroliclone as stabilizer, and 2, 2＇-azobis（isobutyronitrile） as initiator. The modified-titanium dioxide was analyzed with Fourier-transform infrared spectroscopy（FTIR）, UV-Vis spectrophotometer, thermo-gravimetric analysis and transmission microscope. The polymer encapsulation of modified-titanium dioxide and unmodified-titanium dioxide particles was confirmed with FTIR and transmission electron microscope. Results show that compared with unmodified-titanium dioxide, modified-titanium dioxide is more suitable for preparing inorganic core/orclanic shell composites.

Study on the Influence of Ni Modifying on Phase Transformation and Photocatalytic Activity of TiO_2

The Ni-modified TiO2 was synthesized using two methods including co-precipitation(Ni doped TiO2, Ni-TiO2) and wet impregnation(Ni loaded TiO2, Ni/TiO2). The surface and bulk crystalline phases of Ni-modified TiO2 were investigated by using X-ray diffractometry(XRD), UV Raman spectroscopy, TEM, and SEM. It is observed that Ni doping can promote the phase transition and grain size growth of TiO2. Moreover, the propagation of the rutile phase from the bulk into the surface region of TiO2 is increased when the Ni doping amount reaches up to 3%. However, in Ni/TiO2, it is found out that the surface and bulk phase transformation of TiO2 can be inhibited after impregnation of 1% of Ni on the TiO2. Compared with the co-precipitation method, Ni species may be more enriched in the surface of the Ni/TiO2 sample upon adoption of the impregnation method, and the direct contact of anatase particles of TiO2 is avoided. As a consequence, the phase transition in the surface and bulk region of TiO2 can be effectively inhibited by Ni loading. Additionally, the activity of the photocatalytic degradation of RhB on the 3Ni-TiO2-600 ℃ sample is higher than that on the 3 Ni/TiO2-600 ℃ sample. The phase junction formed between anatase and rutile in the surface region of 3Ni-TiO2-600 ℃ may the main reason for its high photocatalytic activity.

Complete removal of phenolic contaminants from bismuth-modified TiO2 single-crystal photocatalysts

Exploring low-cost and highly active photocatalysts is very urgent to accomplish complete removal of phenolic contaminants and overcome the limitations of the existing photocatalysts.In this study,we designed and synthesized noble metal-free TiO2 photocatalysts by introducing bismuth nanoparticles as modifiers of a TiO2 single crystal(Bi-SCTiO2).The Bi-SCTiO2 can make full use of the synergistic effect of a small band overlap and low charge carrier density(Bi)with a high conductivity(single crystal),significantly boosting the separation and migration of the photogenerated charge pairs.Therefore,the Bi-SCTiO2 photocatalyst exhibits a significantly enhanced degradation rate(12 times faster)of 4-nitrophenol than a TiO2 single crystal under simulated sunlight irradiation.Notably,the complete removal of phenolic contaminants is achieved in various water matrices,which not only successfully overcomes the incomplete degradation in many reported photocatalytic systems,but also manifests a significant practical potential for sewage disposal.Therefore,this work presents a new insight in designing and constructing noble metal-free decorated semiconductor single-crystal photocatalysts with excellent activity and cyclability.

Efficient development of Type-Ⅱ TiO_2 heterojunction using electrochemical approach for an enhanced photoelectrochemical water splitting performance

Type‐II‐heterojunction TiO2nanorod arrays(NAs)are achieved by a combination of reduced and pristine TiO2NAs through a simple electrochemical reduction.The heterojunction‐structured TiO2NAs exhibit an enhanced photo‐efficiency,with respect to those of pristine TiO2NAs and completely reduced black TiO2.The improved efficiency can be attributed to a synergistic effect of two contributions of the partially reduced TiO2NAs.The light absorption is significantly increased,from theUV to the visible spectrum.Moreover,the type II structure leads to enhanced separation and transport of the electrons and charges.The proposed electrochemical approach could be applied to various semiconductors for a control of the band structure and improved photoelectrochemical performance.

Tradeoffbetween Narrowing Optical Band Gap and Enhancing Electrical Conductivity of the Metal Nanoparticles-Modified Titanium Oxide Films

The n-type semiconducting titanium oxide thin films are well-known as electron transporting interlayer in photovoltaic cells. The favorable characteristics of interlayers in photovoltaics are high optical transmittance （T%）, wide band gap energy （Eg） and high electrical conductivity （σ）. Modifying titanium oxide films with metal nanoparticles would increase electrical conductivity but reduce optical band gap energy. We developed the sol-gel derived titanium suboxide （TiOx） films modified with silver （Ag） or gold （Au） or copper （Cu） nanoparticles （NPs）. This study explores a tradeoff between narrowing optical band gap and enhancing electrical conductivity of nanostructured TiOx films by controlling the Au- or Ag- or Cu-NPs loading concentrations （mol%） in titania. The Au- and Cu-NPs loading concentration of 4 mol% should meet a tradeoff which yields the higher T%, wider Eg and higher compared to those of pure TiOx films. In addition, since the pure Cu is not thermodynamically stable in ambience as compared to Au and Ag, the stability of as-obtained colloidal CuNPs is also examined. A careful examination of the time evolution of surface plasmon resonance （SPR） bands of CuNPs indicates that their stability is only up to 4 h.

Effects of Metal Oxide Modifications on Photoelectrochemical Properties of Mesoporous TiO2 Nanoparticles Electrodes for Dye-Sensitized Solar Cells

Mesoporous TiO2 （m-TiO2） nanoparticles were used to prepare the porous film electrodes for dye-sensitized solar cells, and a second metal oxide （MgO, ZnO, A1203, or NiO） modifi- cation was carried out by dipping the m-TiO2 electrode into their respective nitrate solution followed by annealing at 500 ℃. Experimental results indicated that the above second metal oxide modifications on m-TiO2 electrode are shown in all cases to act as barrier layer for the interracial charge transfer processes, but film electron transport and interfacial charge recombination characteristics under applied bias voltage were dependent significantly on the existing states and kinds of these second metal oxides. Those changes based on sec- ond metal oxide modifications showed good correlation with the current-voltage analyses of dye-sensitized solar cell, and all modifications were found to increase the open-circuit photo- voltage in various degrees, while the MgO, ZnO, and NiO modifications result in 23%, 13%, and 6% improvement in cell conversion efficiency, respectively. The above observations indi- cate that controlling the charge transport and recombination is very important to improve the photovoltaic performance of TiO2-based solar cell.

Nano-indentation profiles of intrinsic hardness and modulus of films based on silsesquioxane modified with titanium tetrabutoxide

This study is to analyze the influence of the modifier, 5～25 wt % titanium tetrabutoxide (TBO), on the hardness and elastic modulus of the films based on SSO deriving from hydrolytic condensation of (3-glycidoxypropyl)trimethoxysilane (GPMS) and vinyltrimethoxysilane (VMS), by the continuous stiffness measurement (CSM) technique of an instrumented-indentation testing (IIT) device. Films were synthesized by adding the stoichiometric amount of ethylenediamine (EDA) and benzoyl proxide (BPO) to SSO solutions in ethanol, dip-coating over glass substrates, and curing using an appropriate thermal cycle. Intrinsic values of hardness and elastic modulus were determined with the average values in “plateau region” from “four-layer” explanation. And the brittle index of the modified coating systems was analyzed.

In vitro and in vivo evaluation of porous NiTi alloy modified by sputtering a surface TiO_2 film

A uniform and dense TiO2 film was grown on the surface of porous NiTi shape memory alloys(SMAs) successfully by RF magnetron sputtering.The morphology and composition of the surface film were analyzed by using scanning electron microscopy and X-ray photoelectron spectroscopy.The corrosion resistance measurement proved that the surface modified porous NiTi SMAs exhibit better corrosion resistance and over 25% reduction of Ni ion release in the blood of the rabbits in comparing with the samples without surface modification.Moreover,the biocompatibility,as demonstrated by cell adherence and implant surgery,revealed that the cell adherence and bone tissue inducing capability are respectively enhanced over 1.1-1.2 and 9-10 times by sputtering a uniform TiO2 film on the surfaces of porous NiTi SMAs.

Improved conversion efficiency of dye-sensitized solar cells by using novel complex nanostructured TiO_2 electrodes

A novel complex nanostructured TiO2 electrode and fabrication process were proposed and demonstrated to improve the performance of dye-sensitized solar cells(DSSCs).In the proposed process,a nanoporous TiO2 layer was firstly fabricated on the FTO(fluorine-doped tin oxide) conducting substrate by an anodization process,then a nanoparticulate TiO2 film was deposited on the nanoporous TiO2 layer by the screen printed method to form the complex nanostructured TiO2 electrode.The experiments demonstrated that the nanoporous TiO layer can enhance the light scattering,decrease the contact resistance between TiO2 electrode and FTO,and suppress the recombination of I3-ion with the injected electrons of FTO.The process variables are crucial to obtain the optimized performance of DSSCs.By adopting the optimized process,improved conversion efficiency of DSSCs was achieved at AM 1.5 sunlight.