CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Bo Zhao,Qianqian Liu,Guijuan Wei,Jianghao Wang,Xin-Yao Yu,Xiang Li,Hao Bin Wu
CoSe 2 is a potential anode material for sodium-ion batteries in terms of their high sodium storage capacity and tunable properties. However, structural degradation and unstable interphase during the reversible sodiation and de-sodiation lead to fast capacity decay. In this work, we develop a nanocomposite architecture based on CoSe 2 nanoparticles embedded in N-doped carbon matrix with conformal TiO 2 coating (CoSe 2 @NC@TiO 2 ) by using a metal-organic framework-assisted strategy. The small CoSe 2 nanoparticles and N-doped carbon matrix facilitate charge transport and suppress the structural degradation, while the redox-active TiO 2 shell further strengthens the structural and interfacial stability without decreasing the capacity. The as-prepared CoSe 2 @NC@TiO 2 nanocomposite particles deliver a reversible sodium storage capacity of 520 mAh g −1 at 0.1 A g −1 with a capacity retention of 78% after 200 cycles, in contrast to the rapid capacity fading after 50 cycles of the pristine CoSe 2 @NC particles without TiO 2 shell.
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高影响因子
Russian Journal of Physical Chemistry A
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2019
·Vol. 93
·期 6
·1128-1132
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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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高影响因子
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
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2019
·Vol. 43
·期 9
·4473-4482
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IF 3.343
Dixuan Cheng,Gang Cheng,Zhangxing He,Lei Dai,Ling Wang
Summary In this paper, titanium dioxide (TiO 2 ) nanoparticles were employed as catalysts towards V 2+ /V 3+ redox couple of vanadium redox flow battery (VRFB). The effect of TiO 2 phase on the electrocatalytic performance for negative couple was systematically investigated. The electrochemical properties of TiO 2 with different phase were assessed via cyclic voltammetry and electrochemical impedance spectroscopy by using AB as conductive agent. Obtained from the results, anatase TiO 2 (α-TiO 2 ) exhibits superior electrocatalytic activity to rutile TiO 2 (γ-TiO 2 ). The VRFB cell performs well at discharge capacity, voltage efficiency, and energy efficiency by employing α-TiO 2 -modified negative electrode with current density varying between 50 and 100 mA cm −2 . The discharge capacity of α-TiO 2 -modified cell with vanadium ion concentration of 1.6 M comes up to 113.5 mA h at 100 mA cm −2 current density, which is increased by 39.1 mA h after modification for negative electrode. Moreover, the corresponding energy efficiency increases by 7.5% after modification of α-TiO 2 . Experimental results show that TiO 2 is an ideal catalyst for VRFB. Moreover, α-TiO 2 demonstrates superior electrocatalytic performance to γ-TiO 2 towards V 2+ /V 3+ reaction.
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ELECTROCHIMICA ACTA
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2018
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IF 5.116
Yuebin Yang,Hui Xu,Shanxing Wang,Yuanfu Deng,Xianying Qin,Xusong Qin,Guohua Chen
Li-ion batteries have held a dominant position in the energy storage area for decades. However, due to the limitation of its chemistry , the energy density of Li-ion batteries is limited to ∼300 W h kg −1 . In recent years, more attention has been paid to the Li-S batteries that are environmentally friendly, cost-effective and high energy density (theoretical value of cathode: ∼2600 W h kg −1 ). In this study, carbonized polydopamine (C-PDA)-coated hollow carbon nanofibers (CNFs) with TiO 2 nanoparticles interspersed in the void space between the CNF skeleton and carbon coating layer were subtly designed. The C-PDA/TiO 2 /CNF composite (CTC) was integrated with the commercial separator as a polysulfide filter to achieve high-performance Li-S batteries. It is reveals that the CTC coating layer could effectively filter and reactivate the dissolved polysulfides to achieve a stabilized sulfur-based cathode. The Li-S battery assembled by this integrated separator and the regular cathode (sulfur/Ketjen black) with 72.7 wt% of sulfur achieved a high specific capacity and low decay rate (632.5 mAh g −1 at the first cycle and 0.06% per cycle) at 2.0C for 500 cycles. These good results indicate that the C-PDA/TiO 2 /CNF-modified separator could be a promising separator candidate for high performance Li-S batteries.
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RSC Advances
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2018
·Vol. 8
·期 70
·40022-40034
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IF 2.936
Wei Du,Qin Xu,Dangqin Jin,Xiaoyu Wang,Yun Shu,Liming Kong,Xiaoya Hu
This work investigated the feasibility and efficiency of a heterogeneous photo-Fenton catalyst, Fe/Si codoped TiO2, for the degradation of metronidazole (MNZ) under visible light irradiation. The Fe/Si codoped TiO2 was prepared via a facile and simple sol–gel solvothermal process followed by annealing at 480 °C for 4 hours. High resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) measurements revealed that the photo-Fenton process did not change the structure, textural and surface morphologies of this catalyst. Elemental mapping results indicated the good dispersion of Fe and Si ions in TiO2. Nitrogen adsorption and desorption measurements indicated that Si doping increased the surface area of the catalysts. The Fe and Si doping narrowed the band gap of TiO2. They also facilitated the transfer of photo-generated electrons from TiO2 to Fe(III). Under visible light irradiation and the optimum operating conditions, MNZ could be completely degraded in 50 min by this catalyst within a wide pH range. Hydroxyl radicals and holes were verified to be responsible for degrading MNZ. The leaching of iron ions was less than 0.047 ppm even after illuminating the catalyst for 6 hours, indicating the good stability of the Fe/Si codoped TiO2. The as-prepared catalysts with excellent catalytic activity, and remarkable reusability and stability could provide a new insight into the preparation of photocatalysts and have wide applications for antibiotics removal.
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PubMed
高影响因子
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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2018
·
IF 3.779
Yan Yang,Xiqing Xu,Jianxiong Zhao,Bin Wang,Cui Li,Xia Chen,Fang Xu
Saturation magnetization (4π M s ) and ferromagnetic resonance linewidth ( ΔH ) are vital parameters for microwave devices application. The material with high 4π M s and low ΔH is available in microwave frequency. In this work, to synthesize a ferrite material applied to X band, high saturation magnetization LiZnBi ferrite ceramics were selected as matrix. Further, in order to reduce magnetic loss of the LiZnBi ferrites sintered at low temperatures, various nano-TiO 2 were added. Interestingly, the nano-TiO 2 can promote grains growth and suitably enhance saturation magnetization and lower coercivity at low sintering temperature . Meanwhile, the ferromagnetic resonance linewidth ( ΔH ) of the ferrites can also be reduced by introducing more nano-TiO 2 particles. At last, a nano-TiO 2 substituted LiZnBi ferrite ceramics (x = 0.25) with high saturation magnetization (4π M s = ∼3367 G), low coercivity ( H c = ∼146.2 A/m) and low ferromagnetic resonance linewidth ( ΔH = ∼192 Oe) were obtained at 880 °C. The ferrite material is serviceable for X band microwave devices, such as phase shifter and circulator.
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JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
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2018
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IF 3.046
Bang Zhou,Yaqiang Dong,Lei Liu,Liang Chang,Fengqin Bi,Xinmin Wang
The core-shell structured FeSiBCCr@TiO 2 amorphous magnetic powder cores (AMPCs) with excellent comprehensive magnetic properties were successfully prepared using spherical amorphous powders with high quality insulating layer. Scanning electron microscopy, Energy dispersive X-ray spectroscopy analysis, X-ray diffraction, and Fourier transform infrared spectroscopy revealed that the surface of the Fe-based amorphous powders was covered by a continuous amorphous TiO 2 insulation layer. The performances of the AMPCs can be well tuned by changing the thickness of the insulation coating layer, which can be adjusted by controlling the concentration of tetrabutyl titanate (TBOT) in the hydrolysis and condensation reaction system. After annealing at 480 °C for 1 h, the AMPCs with TBOT concentrations of 0.15 ml/g exhibited excellent comprehensive soft magnetic properties, including the highest quality factor of 104.5 at 560 kHz and lowest core loss of 265 mW/cm 3 at f = 100 kHz and B m = 0.05 T. It also maintained a relatively high permeability of 67 up to 5 MHz and superior DC-bias permeability of 68% at a bias field of 100 Oe. This study demonstrated a modified method to develop a novel insulation coating layer to reduce the core loss and improve the magnetic properties of AMPCs.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2018
·
IF 11.698
Xingyu Guo,Xiangqing Li,Lixia Qin,Shi-Zhao Kang,Guodong Li
Development of photocatalysts with high activity and durability for hydrogen generation is extremely desired but still remains a great challenge currently. With Cu nanoparticles (Cu NPs) as a linker between TiO 2 microsphere (TiO 2 MS) and 5, 10, 15, 20- meso -tetra(4-carboxyphenyl)porphyrin (TCPP), a novel nano-micro hybrid (TiO 2 MS-Cu-TCPP) was prepared via a facile method. By bridging TiO 2 MS and TCPP with Cu NPs, the absorption and the electron transfer of TiO 2 MS were greatly improved. When the TiO 2 MS-Cu-TCPP was employed as the photocatalyst for hydrogen evolution, it exhibited higher activity and stability than those of the TiO 2 MS, the TiO 2 MS-Cu and the TiO 2 MS-TCPP, TiO 2 MS-Cu-CuTCPP and TiO 2 MS-TCPP-Cu. The photocatalytic activity was enhanced for about 6 times with respect to that of the pristine TiO 2 MS. The excellent performance for the nano-micro hybrid can be attributed to wide light absorption, more reactive sites, and facilitated interfacial electron transfer owing to the strong interaction between TiO 2 and TCPP with Cu NPs as the linker and cocatalyst. Subsequently, a high and stable photocatalytic activity over the TiO 2 MS-Cu-TCPP nano-micro hybrid was achieved, demonstrating the importance of interfacial modification to a semiconductor photocatalyst. This result gives us a new perspective of constructing special structures for efficient light utilization and electron transfer.
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JOURNAL OF ORGANIC CHEMISTRY
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2018
·
IF 4.805
Zhenhua Dong,Jinwei Yuan,Yongmei Xiao,Pu Mao,Wentao Wang
A rapid and practical protocol for the chemoselective deoxygenation of various aromatic ketones and aldehydes was described, which used a tandem catalyst composed of heterogeneous Pd/TiO2 + homogeneous FeCl3 with the green hydrogen source, polymethylhydrosiloxane (PMHS). The developed catalytic system was robust and scalable, as exemplified by the deoxygenation of acetophenone, which was performed on a gram scale in an atmospheric environment utilizing only 0.4 mol % Pd/TiO2 + 10 mol % FeCl3 catalyst to give the corresponding ethylbenzene in 96% yield within 10 min at room temperature. Furthermore, the Pd/TiO2 catalyst was shown to be recyclable up to three times without an observable decrease in efficiency and it exhibited low metal leaching under the reaction conditions. Insights toward the reaction mechanism of Pd-catalyzed reductive deoxygenation for aromatic ketones and aldehydes were investigated through operando IR, NMR, and GC-MS techniques.
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PubMed
高影响因子
Journal of Materials Chemistry A
·
2015
·Vol. 3
·期 33
·17417-17425
·
IF 7.443
Rui Tang,Longwei Yin
We present a novel Sr-doped TiO2/SrTiO3 nanorod array heterostructure for dye-sensitized solar cells (DSSCs) via a facile two-step hydrothermal process, with a tunable microstructure, optical response and photoelectrical conversion properties. The chemical composition components and microstructures of Sr-doped TiO2/SrTiO3 nanorod array heterostructures are investigated using XRD, XPS, SEM and TEM characterization techniques, respectively. It is shown that the treatment of rutile TiO2 nanorod arrays in Sr(NO3)2 solution results in the self-doping of Sr into the lattice of TiO2 and formation of Sr-doped TiO2/SrTiO3 nanorod array heterostructures, inducing a transition of optical response properties from the ultraviolet region to the visible region. The photogenerated electrons and holes can be effectively separated due to the formation of SrTiO3/Sr-doped TiO2 heterostructures with a uniquely matched band-gap energy structure, resulting in greatly enhanced photoelectric conversion efficiency performance. Electrochemical impedance spectroscopy and photoluminescence results show that the formation of Sr-doped TiO2/SrTiO3 heterostructures can effectively prolong the charge carrier lifetime. The dye loading capacity on the Sr-doped TiO2/SrTiO3 heterostructures can be improved through the functionalization bonding of the hydroxide group on the surface of the electrode material. DSSCs based on the optimized Sr-doped TiO2/SrTiO3 heterostructure photoanode achieve the highest energy conversion efficiency of 4.70% (one sun illumination), nearly 1.5 times higher than the bare rutile TiO2 photoanode (3.10%).
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Journal of Water Process Engineering
·
2015
·
IF 0
Dongfang Zhang,Jiaxun Wang
Liquid-phase photocatalytic oxidation of a secondary diazo dye compound, Congo red (CR, C 32 H 22 N 6 Na 2 O 6 S 2 ) and pharmaceutical phthalylsulfathiazole, was carried out in a cylindrical photochemical reactor on gold-loaded titania systems. The deposition of Au nanoparticles was performed by photochemical deposition methods on the surface of pre-sulphated titania. The detailed structural, compositional and optical characterization and physico-chemical properties of the obtained products are analyzed by X-ray diffraction (XRD), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), high resolution TEM (HRTEM), UV–vis diffuse reflectance spectroscopy (UV–vis DRS), Fourier transformation infrared spectroscopy (FTIR) and photoluminescence spectra (PL) analysis. Notable enhancements in the photocatalytic activity of TiO 2 were achieved by deposition of gold onto titania, which can be attributed to the enhanced surface electron excitation and effective electron-hole separation on gold-deposited TiO 2 nanoparticles. The present study shows that the higher rate of photodegradation observed on Au-TiO 2 at pH 6.5 can be correlated to the ratios of the concentrations of the ionized to the neutral dye molecules and also to the higher concentration of hydroxylated surface, which are able to effectively scavenge photogenerated valence band holes. Accumulation of the holes in the semiconductor particles increases the probability of formation of excited oxygen atom which is a reactive species readily oxidizing the organic dye molecule or environmental pollutant such as pharmaceutical phthalylsulfathiazole. The reaction mechanism of the photocatalytic system was detected by a photoluminescence method using terephthalic acid as a probe molecule.
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