查找使用阿拉丁产品的科研文献

CdS/CdSe co-sensitized SnO2 photoelectrodes for quantum dots sensitized solar cells

Yibing Lin,Yu Lin,Yongming Meng,Yongguang Tu,Xiaolong Zhang

SnO 2 nanoparticles were synthesized by hydrothermal method and applied to photo-electrodes of quantum dots-sensitized solar cells (QDSSCs). After sensitizing SnO 2 films via CdS quantum dots , CdSe quantum dots was decorated on the surface of CdS/SnO 2 photo-electrodes to further improve the power conversion efficiency. CdS and CdSe quantum dots were deposited by successive ionic layer absorption and reaction method (SILAR) and chemical bath deposition method (CBD) respectively. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to identify the surface profile and crystal structure of SnO 2 photo-electrodes before and after deposited quantum dots. After CdSe co-sensitized process, an overall power conversion efficiency of 1.78% was obtained in CdSe/CdS/SnO 2 QDSSC, which showed 66.4% improvement than that of CdS/SnO 2 QDSSC.

A silica co-electrodeposition route to highly active Ni-based film electrodes

Lian-Kui Wu,Ji-Ming Hu,Jian-Qing Zhang,Chu-Nan Cao

We report a novel silica co-electrodeposition route to prepare highly active nickel films. Firstly, Ni–SiO2 composite film was fabricated on a stainless steel substrate by electrodeposition, and then the SiO2 template was removed in alkaline electrolyte by consecutive cyclic voltammetry scans, leading to the formation of a porous Ni (po-Ni) matrix. The structure and morphology of the obtained films were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The highly porous property of the po-Ni matrix is believed to be quite favourable for electrochemical applications. The electrochemical properties of the po-Ni film were evaluated by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) and steady-state polarization curves. The results showed that the porous Ni derived from the Ni–SiO2 composite film exhibits good electrochemical performance for potential use as a supercapacitor material and catalyst for water splitting.

Large-Scale Colloidal Synthesis of Co-doped Cu2SnSe3 Nanocrystals for Thermoelectric Applications

Zhang Aijuan,Chen Qiufan,Yao Wei,Yang Dingfeng,Wang Guoyu,Zhou Xiaoyuan

The large-scale colloidal synthesis and thermoelectric (TE) properties of Co-doped Cu 2 SnSe 3 (CCTSe) alloys are investigated for the first time. The TE properties of the CCTSe bulks were measured in the temperature range from 300 K to 715 K. A large increment in the Seebeck coefficient and a dramatic reduction in the lattice thermal conductivity was observed in CCTSe compounds, and the dimensionless TE figure␣of merit ZT reaches a peak value of 0.63 at 715 K. These observations demonstrate an exciting scientific opportunity to raise the figure-of-merit of colloidally synthesized quaternary chalcogenide nanocrystals via optimized doping.

RGO and Three-Dimensional Graphene Networks Co-modified TIMs with High Performances

Bo Tang,Zhengwei Wang,Huang Weiqiu,Sen Li,Tingting Ma,Haogang Yu,Xufei Li

With the development of microelectronic devices, the insufficient heat dissipation ability becomes one of the major bottlenecks for further miniaturization. Although graphene-assisted epoxy resin (ER) display promising potential to enhance the thermal performances, some limitations of the reduced graphene oxide (RGO) nanosheets and three-dimensional graphene networks (3DGNs) hinder the further improvement of the resulting thermal interface materials (TIMs). In this study, both the RGO nanosheets and 3DGNs are adopted as co-modifiers to improve the thermal conductivity of the ER. The 3DGNs provide a fast transport network for phonon, while the presence of RGO nanosheets enhances the heat transport at the interface between the graphene basal plane and the ER. The synergy of these two modifiers is achieved by selecting a proper proportion and an optimized reduction degree of the RGO nanosheets. Moreover, both the high stability of the thermal conductivity and well mechanical properties of the resulting TIM indicate the potential application prospect in the practical field.

High-frequency pulse electrodeposition and characterization of Ni–Co/ZrO2 nanocomposite coatings

Jiang Yancheng,Xu Yunhua,Feng Guitao,Yao Hanchao

Ni–Co/ZrO 2 nanocomposite coatings were produced by high-frequency pulse electrodeposition in a modified Watt’s bath containing ZrO 2 particles. The surface morphology, microstructure, and high temperature oxidation resistance of the coatings were characterized by scanning electron microscopy with energy dispersive X-ray spectroscopy, X-ray diffraction, and isothermal oxidation tests. It was found that the presence of ZrO 2 particles resulted in changes in the morphology and structure of the coatings. The results also confirmed the nanostructure and uniform distribution of ZrO 2 particles of Ni–Co/ZrO 2 nanocomposite coatings. The addition of ZrO 2 did not change the preferred orientation (200), but remarkably affected the relative intensity of planes of Ni–Co alloy. The influence of duty cycle, average current density, and frequency on the amount of incorporated ZrO 2 particles in the Ni–Co/ZrO 2 nanocomposite has been also investigated. The Ni–Co/ZrO 2 nanocomposite coatings with highest ZrO 2 content (11.6 wt%) were prepared under the condition of duty cycle of 40 %, average current density of 5 A dm −2 , and frequency of 100 kHz. Moreover, the embedded ZrO 2 particles significantly improved the high temperature oxidation resistance of Ni–Co alloy coatings. The oxidation rate of Ni–Co/ZrO 2 nanocomposite coatings decreased with increasing the ZrO 2 content of the coatings.

Removal of methylene blue from aqueous solutions using Poly(AA-co-DVB)

Jia Du,Luanluan Zhang,Hejun Gao,Yunwen Liao

Selective Hydrodeoxygenation of Lignin-Derived Phenols to Cyclohexanols over Co-Based Catalysts

Xiaohao Liu,Wenda Jia,Guangyue Xu,Ying Zhang,Yao Fu

Cyclohexanols are important feedstock for polymers, spices, and medicines production in industry. In this work, a series of cobalt-based catalysts with different supports were prepared and used to catalyze lignin-derived phenols to cyclohexanols. Among the catalysts, Co/TiO2 showed the best hydrodeoxygenation (HDO) activity. An equivalent of propylcyclohexanol (>99.9%) was achieved under 1 MPa H2, 200 °C for 2 h. According to the characterization results of transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface area analysis, powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H2-TPR), hydrogen temperature-programmed desorption (H2-TPD) and NH3-TPD, the particle size and dispersion of Co could have important influence on catalytic activity. For Co/TiO2, the SMSI effect may significantly affect the catalytic activity. The influences of different temperature, H2 pressure and reaction time on the eugenol conversion by Co/TiO2 were explored. 99% yield of propylcyclohexanol could even be obtained under 0.4 MPa H2, 180 °C for 8 h. This should be the mildest condition that has been reported for HDO of eugenol to propylcyclohexanol catalyzed by non-noble metal catalyst. On the basis the mechanism and substrates extension studies, all the Co-based catalysts selected in this study showed high activity to cleave the Caryl–OCH3 bond before the hydrogenation of the aromatic ring when the −OCH3 group substituted at ortho-position.

Colossal permittivity and dielectric relaxation of (Li, In) Co-doped ZnO ceramics

Dong Huang,Zhifu Liu,Yongxiang Li,Yun Liu

In this study, a colossal permittivity up to 3800 and a low dielectric loss of 0.11 at 1 kHz have been obtained from the (Li, In) co-doped ZnO ceramic [Zn (1−2x) (Li, In) x O] when x was 0.5%. Electric modulus spectroscopy and impedance analysis were used to investigate the origin of its high permittivity. Two relaxation peaks and a dielectric anomaly were observed in the temperature range of 293–363 K. According to the Debye relaxation theory, the low- and high-temperature relaxation peaks with activation energies of 0.09 eV and 0.29 eV, have been attributed to the hopping of singly and doubly charged oxygen vacancies , which are created by lithium and indium ions doping and oxygen deficiency during sintering process. After thermal treatment in an oxidizing atmosphere, the peaks related to the singly and doubly charged oxygen vacancies disappear and the permittivity reduces to ∼460 at room-temperature. From the X-ray photoelectron spectra (XPS), the concentrations of oxygen vacancies decrease after the O 2 -annealing process. The results reveal that the oxygen defects would be the main origin of the colossal permittivity of co-doped ZnO at room-temperature range.

Luminescence and cathodoluminescent properties of monoclinic Y2WO6 co-doped with Dy-Bi

Peiju Hu,Wei Zhang,Zhengfa Hu,Zuyong Feng,Lun Ma,Xiuping Zhang,Xia Sheng,Li Luo,Yinhai Wang

Dy-Bi co-doped yttrium tungstate crystal materials were synthesized by high temperature solid-state method. To reveal the photoluminescence features and properties of the samples, some measurements have been taken. It turned out that different Bi 3 + ${}^{3+}$ concentrations play obvious influence in emission performance, and show visible light emission under ultraviolet light excitation. Besides, the effect of temperature on phase structure of samples has also been studied here. Superhigh X-ray luminescence of the phosphors exhibited the promising application in the field of high energy detection. The X-ray irradiation crystal resistance stability of the phosphors has also been investigated through the subsequent testing of XRD and spectra.

Poly(lactide-co-glycolide)/Hydroxyapatite Porous Scaffold with Microchannels for Bone Regeneration

Ning Zhang,Yang Wang,Wenpeng Xu,Yong Hu,Jianxun Ding

Mass transfer restrictions of scaffolds are currently hindering the development of three-dimensional (3D), clinically viable, and tissue-engineered constructs. For this situation, a 3D poly(lactide-co-glycolide)/hydroxyapatite porous scaffold, which was very favorable for the transfer of nutrients to and waste products from the cells in the pores, was developed in this study. The 3D scaffold had an innovative structure, including macropores with diameters of 300–450 μm for cell ingrowth and microchannels with diameters of 2–4 μm for nutrition and waste exchange. The mechanical strength in wet state was strong enough to offer structural support. The typical structure was more beneficial for the attachment, proliferation, and differentiation of rabbit bone marrow mesenchymal stem cells (rBMSCs). The alkaline phosphatase (ALP) activity and calcium (Ca) deposition were evaluated on the differentiation of rBMSCs, and the results indicated that the microchannel structure was very favorable for differentiating rBMSCs into maturing osteoblasts. For repairing rabbit radius defectsin vivo, there was rapid healing in the defects treated with the 3D porous scaffold with microchannels, where the bridging by a large bony callus was observed at 12 weeks post-surgery. Based on the results, the 3D porous scaffold with microchannels was a promising candidate for bone defect repair.Keywords:poly(lactide-co-glycolide);hydroxyapatite;porous scaffold;microchannel;cell ingrowth;mass exchange;bone tissue engineering

Fabrication of Yb:Sc2O3 laser ceramics by vacuum sintering co-precipitated nano-powders

Qiang Liu,Zhengfa Dai,Dariusz Hreniak,Shanshan Li,Wenbin Liu,Wei Wang,Wei Luo,Chaoyu Li,Jiawei Dai,Haohong Chen,Huamin Kou,Yun Shi,Yubai Pan,Jiang Li

Ytterbium doped scandium oxide (Yb:Sc 2 O 3 ) nano-powders were synthesized by a co-precipitation method. Ammonium hydrogen carbonate (NH 4 HCO 3 ) and ammonia sulfate ((NH 4 ) 2 SO 4 ) were used in the precipitation process as the precipitant and dispersing agent, respectively. Structural properties and morphology of the precursor and nano-powders were investigated by BET, XRD , and SEM measurements. Ultra-fine and low agglomerated 5 at%Yb:Sc 2 O 3 powders with the average particle size of 86 nm were obtained after calcination of the precipitate at 1100 °C for 5 h, that was found to be the optimal temperature for preparation of 5 at%Sc 2 O 3 powders for further sintering. 5 at%Yb:Sc 2 O 3 transparent ceramics with in-line transmittance of 73.9% at 1100 nm and average grain size of 182 μm were fabricated by vacuum sintering of the optimal powder at 1850 °C for 10 h. The microstructure, the spectroscopic properties and the gain characteristics of obtained 5 at%Yb:Sc 2 O 3 ceramics were also studied and discussed.

Effective removal of strontium from wastewater using Co-doped layered sodium vanadosilicate

Xinru Li,Jiale Li,Zhichao Liu,Can Liu,Yafei Guo,Tianlong Deng

The effective removal of strontium (Sr) from radioactive wastewater is essential for human health and ecological sustainability. However, due to the existence of a large number of coexisting ions, the selective removal of Sr 2+ from it remains a significant challenge. Herein, three novel metal-doped sodium vanadosilicates were developed by structural regulation. It was found that Co-doping can not only significantly reduce the dissolution loss of vanadosilicate (NaVOSi) from the adsorbent in extreme environments by adjusting the orbital energy distribution, energy band structure, bond length, and bond energy of sodium vanadosilicate crystals, but also further enhance the adsorption performance by reducing its zeta potentials and agglomeration phenomenon. The maximum adsorption capacity of the developed adsorbent (Co-NaVOSi) was up to 319.10 mg·g −1 within 5 min. When applied to Sr 2+ removal from simulated wastewater, the distribution coefficients of Sr 2+ reached 2943.15 mL·g −1 , and the separation coefficients between Sr 2+ and coexisting ions were above 64. DFT calculations further revealed the highly selective removal mechanism of Sr 2+ from wastewater. In addition, NaNO 3 was proved to be an efficient eluent. The excellent properties above make NaVOSi an excellent candidate for effectively removing Sr 2+ from wastewater.