TALANTA
·
2019
·
IF 4.916
Xiaolan Liu,Man He,Beibei Chen,Bin Hu
Increasing use of TiO 2 nanoparticles (NPs) leads to an accumulation in environment and a risk to human. In this work, an on-line monolithic capillary microextraction (CME)-inductively coupled plasma mass spectrometry (ICP-MS) method was developed for sensitive determination of TiO 2 NPs in environmental water samples. With the presence of citric acid , TiO 2 NPs can be selectively adsorbed on the poly(acrylamide)-vinylpyridine-methylene bis-(acrylamide) (poly(AA-VP-Bis)) monolithic column at pH 1, whereas Ti ions cannot be adsorbed. Factors affecting the extraction efficiency such as sample pH, concentration of citric acid and elution conditions were carefully investigated. Under the optimum conditions, a detection limit of 0.63 μg L −1 for TiO 2 NPs and a sample throughput of 6 h −1 were achieved. The method can be applied to the determination of TiO 2 NPs in the size range of 5–100 nm. The developed method was then applied to the analysis of TiO 2 NPs in the East Lake water and Yangtze River water, and recoveries of 84–109% were obtained for spiked samples. Compared with other reported methods for the determination of metal oxide NPs, the developed on-line monolithic CME-ICP-MS has the merits of simple operation, high throughput and no need for digestion before ICP-MS detection.
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高影响因子
Journal of Physical Chemistry C
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2019
·
IF 4.309
Guanyun Zhang,Chenxiao Chu,Jian Yang,Chen-Ho Tung,Yifeng Wang
By aerobic calcination of a new titanium-oxide cluster (TOC) isolated from water, that is, [Ti6O8(OH2)20]·(2,7-NDS)4·2HCl·14H2O (Ti6-NDS; 2,7-NDS = 2,7-naphthalenedisulfonate), porous anatase TiO2 was facially prepared. The sample obtained at 400 °C exhibited a surface area of 108 cm3 g–1 and an average pore diameter of 16 nm. When used as an anode material for a sodium-ion battery (SIB), it showed larger specific capacity and far superior rate performance than the other TiO2 samples, including those prepared from another three TOCs under the same conditions or from Ti6-NDS under different conditions and the one obtained from a commercial source. The mechanistic study indicates that the hierarchical structure surrounding the Ti-oxide cores of Ti6-NDS is pivotal for the formation and the SIB performance of the porous TiO2. This surfactant-free and catalyst-free strategy for the fabrication of TiO2 materials with special morphologies by thermal transformation of a TOC provides a new optional protocol for the preparation of promising materials stable and efficient in SIBs.
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APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Jiuxuan Zhang,Hong Jiang,Yefei Liu,Rizhi Chen
ZIF-derived N-doped carbon (CN) materials were modified in this work by TiO 2 nano-islands with oxygen vacancies (O V ) through a sol-gel method and subsequent thermal treatment. By loading Pd nanoparticles (NPs) on CN@TiO 2 , Pd@CN@TiO 2 catalysts were fabricated. Superior catalytic performance of Pd@CN@TiO 2 was found in the selective phenol hydrogenation to cyclohexanone , with a TOF of 30.1 h −1 , 2.2-fold as high as that of Pd@CN. The synergistic effect of CN and TiO 2 nano-islands was responsible for the superior catalytic performance. More O V was generated due to the high specific surface area of CN. At the same time, CN could also enhance the hydrophilicity , and adsorb more phenol in non-planar fashion. The TiO 2 nano-islands with O V could improve the Pd dispersion, make more Pd element on the support surface, strengthen the antioxidizability of Pd and induce electron-rich Pd NPs. Furthermore, the as-fabricated Pd@CN@TiO 2 showed good recyclability in the phenol hydrogenation, and also exhibited excellent catalytic performance in the catalytic hydrogenation of phenol with diverse functional groups. These findings provide the feasibility of using the high-performance catalysts for the hydrogenation of phenol derivatives.
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APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Di Zhang,Pin Ma,Shuo Wang,Mingpeng Xia,Sidong Zhang,Dongmei Xie,Xiaowen Zhou,Yuan Lin
Recently, the pre-synthesized oil-soluble quantum dots (QDs) have triggered great interests due to advantages of monodispersity, stability and easy synthesis. Aggregation of QDs is the reason for low loading and poor efficiency during the in situ ligand exchange linker-assisted assembly process of preparing photovoltaic devices. In this work, we modify TiO 2 films with 4-mercaptobenzoic acid (MBA) as linkers and adjust modification time (MT) of MBA on the surface of TiO 2 films. As the MT increases from 0 to 6 min, even 360 min, loading amount of QDs and photovoltaic performance improve first and then decrease. The results of line scan in cross-sectional view of photoanodes show that QDs uniformly distribute throughout the short-MT films thickness, while obvious aggregation occur in the surface of long-MT films. The best device with 3 min of MBA modification exhibits an optimal efficiency of 5.58%.
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ChemCatChem
·
2018
·Vol. 11
·期 3
·1057-1063
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IF 4.674
Gan Wang,Lijuan Zhang,Baolin Yan,Jianmin Luo,Xintai Su,Fan Yue
Graphical It's a vacancy-rich world ! During the liquid-nitrogen quenching process, the isolated O atoms on the TiO 2 surface are partially frozen and lose the opportunity to return the crystallographic sites, leaving abundant oxygen vacancy on the surface. The oxygen vacancy-rich TiO 2 prepared via liquid-nitrogen quenching exhibited outstanding advantages on photocatalytic H 2 evolution. Development of novel methods to obtain highly active catalysts for photocatalytic hydrogen evolution is desired. This work reports a facile preannealing-quenching strategy to synthesize oxygen vacancy-rich anatase TiO 2 hollow spheres. TiO 2 hollow spheres are first synthesized via a versatile kinetics-controlled coating method and then subjected to high temperature preannealing followed by rapid quenching in liquid-nitrogen (−196 °C). The as-quenched samples appear light grey suggesting the presence of abundant surface oxygen vacancies, which are subsequently confirmed by the comprehensive analyses of XRD, XPS and EPR spectra. The oxygen vacancies induced by quenching process are proved to have promoted the light adsorption and inhibited the recombination of photo-induced charges for TiO 2 hollow spheres, which obviously improve the photocatalytic performance of those samples. The results showed that the TiO 2 hollow spheres quenched at 500 °C exhibited a robust stability and the most excellent photocatalytic performance for hydrogen evolution (413.5 μmol h −1 ) over other quenched samples and it displayed 1.51 times higher performance than that of samples normally cooled at 500 °C (273.7 μmol h −1 ). Herein, this liquid-nitrogen quenching strategy presented here provides an effective route for the synthesis of high-performance TiO 2 for water splitting and have a promising prospect in the other application.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2019
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IF 4.175
Xiaowang Lu,Xiazhang Li,Feng Chen,Zhigang Chen,Junchao Qian,Qinfang Zhang
The novel nitrogen doped two-dimensional CeO 2 –TiO 2 nanosheets with a thickness of less than 5 nm were synthesized by a facile impregnation method using Chinese rose petals as biological templates. The detailed characterization by field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) exhibited that the CeO 2 –TiO 2 composites exactly duplicated the microstructure of Chinese rose petal and the self-owned nitrogen was successfully doped into the CeO 2 –TiO 2 composites, which could enhance the visible light absorption efficiency. UV–Vis diffuse reflection spectroscopy (DRS), photocurrent measurement (PM), electrochemical impedance spectroscopy(EIS) and photoluminescence spectroscopy (PL) were used to analyze the electrons and holes separation efficiency, which revealed that CeO 2 and TiO 2 formed well-defined hetero junctions promoting the effective separation of photogenerated electrons and holes. The photocatalytic activity of the samples was evaluated by photocatalytic degradation of dibenzothiophene (DBT) in model oil. The amount of hydrogenperoxide (H 2 O 2 ) and photocatalysts , the molar ratios of Ce and Ti in CeO 2 –TiO 2 composites as photocatalytic reaction conditions were investigated. Results showed that the removal rate of DBT could reach 93.7% under visible light irritation for 3 h, when the molar ratio of Ce/Ti was 1/1, the mass ratio of photocatalyst/DBT was 1/2 and the molar ratio of H 2 O 2 /DBT was 2/1. The trapping experiments confirmed that the photoinduced active species (•OH radical) was responsible for the degradation of DBT. Further studies demonstrated that DBT was converted to the corresponding sulfone, which could be extracted by the polar solvent. Moreover, a plausible mechanism for the photocatalytic oxidative desulfurization of this nanocomposite was proposed.
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Sustainable Energy & Fuels
·
2019
·Vol. 3
·期 11
·3234-3243
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IF 4.912
Shiyi Deng,Yunjiao Li,Qiongyu Dai,Jiamin Fu,Yongxiang Chen,Junchao Zheng,Tongxing Lei,Jia Guo,Jing Gao,Wei Li
The elevation of energy density is the constant pursuit of the lithium-ion battery industry. LiNiO2 has reacquired recognition because it exhibits high capacity without an increase in the cut-off voltages. To address the flaws of this kind of cathodes, herein, trace nano-TiO2-modified LiNiO2 was synthesized via a simple solid-state method. Via combined characterization, the Ti element was verified to be doped into the bulk lattice and located at the transition-metal sites; after Ti doping, the Ni2+ content was clearly increased due to charge balance, followed by an increase in the Li/Ni disorder. The doped Ti and the as-generated Ni pillar mutually facilitated the stabilization of the material structure and benefitted the Li+ de/insertion. Nanosized TiO2 participating in the calcination process could effectively homogenize the size of the primary particles, adjust the surface morphology and reduce the specific surface area of the material. This morphological regulation may be favorable for reducing the contact area of the cathode with the electrolyte and establishing a stable electrode/electrolyte interface, where some detrimental side-reactions take place. With respect to electrochemical properties, Ti doping could decrease the electrode polarization, lower the impedance and promote the Li+ transfer. As a result, the Ti-modified LiNiO2 cathodes, especially the 0.2% Ti-doped (Ti-2) material, presented enhanced electrochemical performances.
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Materials Research Express
·
2019
·Vol. 6
·期 9
·0950c3
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IF 1.449
Qianzhu Mu,Yanfeng Sun,Aiying Guo,Xiazhao Yu,Xiaoyue Xu,Aijun Cai,Xiuping Wang
A series of Fe3O4–TiO2 composites were successfully synthesized using Chlorella pyrenoidosa as a bio-template. C. pyrenoidosa is not only a promising bio-template for obtaining Fe3O4 and TiO2 nanoparticles (NPs) but is also a natural dye sensitizer source that improves the photocatalytic activity of the TiO2 NPs under visible light. The bandgap energy of Fe3O4–TiO2 is narrower than that of TiO2 due to the coupling between the Fe3O4 and TiO2 NPs. The coupling and dye-sensitization lead to the rapid separation and suppressed recombination of electron-hole pairs in Fe3O4–TiO2, which enhances the photocatalytic activity of TiO2 under visible light. The photocatalytic activity of the as-prepared composites was evaluated by degrading a rhodamine B (RhB) aqueous solution under visible-light irradiation. Fe3O4–TiO2 exhibits a high degradation efficiency for RhB, and can be withdrawn from solution easily using an external magnetic field.
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Polymers
·
2019
·Vol. 11
·期 8
·1293
·
IF 3.164
Xuejuan Shi,Xiaoxiao Zhang,Liang Ma,Chunhui Xiang,Lili Li
Chitosan/cellulose acetate (CS/CA) used as a biopolymer systema, with the addition of TiO2as photocatalyst (C-T/CA) were fabricated by alternating electrospinning/electrospraying technology. The uniform dispersion of TiO2and its recovery after the removal of methyl orange (MO) was achieved by incorporating TiO2in CS electrosprayed hemispheres. The effects of pH values, contact time, and the amount of TiO2on adsorption and photocatalytic degradation for MO of the C-T/CA were investigated in detail. When TiO2content was 3 wt %, the highest MO removal amount for fiber membranes (C-T-3/CA) reached 98% at pH value 4 and MO concentration of 40 mg/L. According to the data analysis, the pseudo-second-order kinetic and Freundlich isotherm model were well fitted to kinetic and equilibrium data of MO removal. Especially for C-T-3/CA, the fiber membrane exhibited multiple layers of adsorption. All these results indicated that adsorption caused by electrostatic interaction and photocatalytic degradation were involved in the MO removal process. This work provides a potential method for developing a novel photocatalyst with excellent catalytic activity, adsorbing capability and recycling use.Keywords:TiO2;chitosan;electrospinning;electrospraying;methyl orange;photocatalytic degradation
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ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Ebrahim Ataeivarjovi,Zhigang Tang,Jian Chen,Zhijun Zhao,Guo Dong
Currently, there is strong interest in carbon capture and absorption as a means of reducing carbon dioxide emissions and combating climate change. Unfortunately, the current and traditional methods to achieve such goals are not economical, because they require a huge absorption–desorption plant with high investment and operating costs and high recycle rates of chemical absorbers. In this paper, we propose a novel CO2 capture method combining dimethyl carbonate as a physical solvent and polydimethylsiloxane (PDMS)/TiO2 nanocomposite as a desorption membrane. The effects of TiO2 concentration, feed temperature, and permeate pressure on the pervaporation process for CO2 capture were studied. Results showed that the addition of TiO2 nanoparticles (up to 5 wt %) resulted in 3.61 kg/m2·h flux and 44.68 selectivity of the membrane. The presence of TiO2 nanoparticles in the PDMS membrane not only increased the performance of membrane’s but also reduced (about 72%) energy consumption. To corroborate our experimental findings, a simple simulation was conducted by Gaussian 09. The modeling results demonstrated that the incorporation of TiO2 nanoparticles to the PDMS led to favorable absorption of CO2 compared with the composite one. These results indicate a novel and promising method to capture CO2 effectively and economically for industrial purposes.
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Russian Journal of Physical Chemistry A
·
2019
·Vol. 93
·期 6
·1128-1132
·
IF 0.581
Xuqiang Ji,Niu Yusheng,Xu Yuanhong
Abstract The design and development of excellent microwave absorption (MA) material is significant for healthcare, electronic, and security industries. Herein, a sophisticated composite with the advantages of large interlayer space, nanoparticles with small size, and hierarchical nanostructure (core@shell@void@shell configuration) simultaneously is demonstrated for the first time. Such unique SiO 2 @TiO 2 nanoparticle was fabricated via a multi-step process. Associating maximum reflection loss value can reach –35.2 dB in certain frequency of 11 GHz and thickness of 3.0 mm. Small-sized TiO 2 nanoparticles (about 6 nm) in first coating and large gap between TiO 2 coating layers are significantly critical for the superior MA performance. Our work points a new direction to rationally construct high-performance microwave absorber.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Yunyang Wang,Changzhu Yang,Ayan Chen,Wenhong Pu,Jianyu Gong
Core-shell and yolk-shell Au@TiO 2 NPs were successfully synthesized, and the morphology differences were observed. Its photocatalytic activity was evaluated by photocatalytic oxidation of gaseous toluene under visible light illumination. The results indicated that yolk-shell Au@TiO 2 exhibited superior photocatalytic properties and demonstrated a good stability. Almost 57.3% of gaseous toluene was removed over 0.14 at% yolk-shell Au@TiO 2 in 3 h. It could also be reused for several times without corrosion. Furthermore, the comprehensive effect of LSPR response of Au, high cavity volume of yolk-shell structure, larger specific surface area, more mesoporous and the existence of Ti 3+ were all benefit for the photocatalytic process. ESR tests also confirmed that h + , OH, O 2 − and Ti 3+ generated from yolk-shell Au@TiO 2 were the main active species in the photocatalytic degradation progress of gaseous toluene under visible light irradiation.
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