查找使用阿拉丁产品的科研文献

ZIF-67 derived Co/N carbon hollow fiber membrane with excellent decontamination performance

Jia Xie,Yingpeng Yang,Hao Zhang,Saisai Chen,Zhengjun Lv,Yujun Zhou,Junwen Qi,Xiuyun Sun,Jiansheng Li

Advanced oxidation processes (AOPs) were appealing wastewater treatment options yet practices were hampered by reactor design and diminished performance in complex water matrices. Herein, one-step-pyrolysis strategy was proposed for large-scale synthesis of ZIF-67 derived conductive Co/N carbon hollow fiber ultrafiltration membrane to achieve exceptional availability of catalytic sites and interference prevention from macro molecular substances by size exclusion. Benefitting from the microenvironment modulation and electric field assistance (−1 V, membrane as the cathode), the bisphenol A (as a model micropollutant) can be efficiently removed with enhanced mass transfer of flow-through process (modified apparent reaction rate constant of 1260 μM g cat -1 s −1 ) and the active cobalt species were cycled via electroreduction thus showing exceptional sustainability with nearly zero Co leaching even after 24 h operation. The synergy effects between separation and catalysis alleviated the deteriorated AOPs efficiency and membrane fouling caused by macromolecular organic matter. The integrated membrane system provides new insight into rational design of catalytic membrane and system engineering for advanced water purification.

Synergistic effects of Bi and N doped on ZnO nanorods for efficient photocatalysis

N.R. Khalid,Hamid Ishtiaq,Faisal Ali,M.B. Tahir,Sumaira Naeem,A. Ul-Hamid,M. Ikram,T. Iqbal,M. Rizwan Kamal,Hussein Alrobei,Meshal Alzaid,A. Dahshan

The fast pace of industrial growth during the current decade has seen a large family of dyes employed copiously in the production of various products such as paper and ink. These dyes pollute earth's ecosystems. Researchers look at various ways to degrade these dyes including the use of suitable nanomaterials . ZnO is an important semiconductor material that can be employed for this purpose. In this research work, we optimized the photocatalytic capability of ZnO by co-doping it with 1–7 wt% of Bi and N. The synthesized Bi and N co-doped ZnO nanorod samples showed excellent photocatalytic behavior towards Rhodamine-B (RhB). It was confirmed using XRD and SEM that (5, 2.5) wt.% Bi/N co-doped ZnO nanorods exhibited unique morphology and structure. EDX successfully assessed the elemental composition of the synthesized samples. To provide further insight into its microstructure, the HRTEM and SAED analysis were performed. Optical properties were determined using PL and UV–Visible spectroscopy. The prepared nanorod material degraded almost 89% of RhB in 180 min. The superior degradation ability of co-doped ZnO material when exposed to visible portion of sunlight spectrum is credited to the decrease in the recombination rate of charges and an increase in the depth penetration of photons. The degradation efficiency of Bi/N co-doped ZnO material is enhanced due to reduced recombination rate and increased production of number of defects and oxygen vacancies .

Organic Crosslinked Polymer-Derived N/O-Doped Porous Carbons for High-Performance Supercapacitor

Jianhao Lao,Yao Lu,Songwen Fang,Fen Xu,Lixian Sun,Yu Wang,Tianhao Zhou,Lumin Liao,Yanxun Guan,Xueying Wei,Chenchen Zhang,Yukai Yang,Yongpeng Xia,Yumei Luo,Yongjin Zou,Hailiang Chu,Huanzhi Zhang,Yong Luo,Yanling Zhu

Supercapacitors, as a new type of green electrical energy storage device, are a potential solution to environmental problems created by economic development and the excessive use of fossil energy resources. In this work, nitrogen/oxygen (N/O)-doped porous carbon materials for high-performance supercapacitors are fabricated by calcining and activating an organic crosslinked polymer prepared using polyethylene glycol, hydroxypropyl methylcellulose, and 4,4-diphenylmethane diisocyanate. The porous carbon exhibits a large specific surface area (1589 m2·g−1) and high electrochemical performance, thanks to the network structure and rich N/O content in the organic crosslinked polymer. The optimized porous carbon material (COCLP-4.5), obtained by adjusting the raw material ratio of the organic crosslinked polymer, exhibits a high specific capacitance (522 F·g−1at 0.5 A·g−1), good rate capability (319 F·g−1at 20 A·g−1), and outstanding stability (83% retention after 5000 cycles) in a three-electrode system. Furthermore, an energy density of 18.04 Wh·kg−1is obtained at a power density of 200.0 W·kg−1in a two-electrode system. This study demonstrates that organic crosslinked polymer-derived porous carbon electrode materials have good energy storage potential.Keywords:supercapacitor;organic crosslinked polymer;porous carbon;electrochemistry

Copper-Promoted One-Pot Sandmeyer-Type Reaction for the Synthesis of N-Aryltriazoles

Menghan Cui,Rong Wang,Qing Yang,Chunxiang Kuang

Herein, we report the copper-catalyzed one-pot Sandmeyer-type reaction of aromatic amines with triazoles to afford N-aryl-1,2,3-triazoles. Diazonium salts, formed from aromatic amines and tert-butyl nitrite in the presence of fluoroboric acid, reacted with triazoles in a copper-catalyzed Sandmeyer-type reaction. The reaction proceeded under mild conditions to afford N-aryltriazoles in moderate to good yields. This method is amenable to a wide range of aromatic amines and triazoles and shows diverse functional group tolerance. Inhibition of the reaction upon the addition of free radical scavengers suggested a radical pathway, in which the aryl radical, copper, and triazole formed a complex that underwent reductive elimination to give aryltriazole compounds; this is consistent with the mechanism underlying the Sandmeyer reaction. Thus, we demonstrate a new effective strategy for the construction of C–N bonds via Sandmeyer-type reactions and a valuable alternative approach for the synthesis of aryltriazole derivatives.

Soot formation in n-heptane/air laminar diffusion flames: Effect of toluene addition

Xiaokang Nie,Jiawei Qi,Shunjie Feng,Ya Liu,Bingbing Qiu,Huaqiang Chu

The mixture of n-heptane and toluene is regarded as surrogate fuel for diesel. Under the premise of a certain carbon flow rate , the particle size, nanostructure , microcrystalline size and soot deposition morphology of three kinds of fuel laminar diffusion flames were studied by Transmission Electron Microscopy (TEM), High Resolution Transmission Electron Microscopy (HRTEM), X-ray diffractometer (XRD) and Field Emission Scanning Electron Microscopy (FESEM). The three fuels were pure n-heptane (T0), toluene / n-heptane blends with 5 vol% (T5) and 10 vol% (T10) toluene, respectively. Thermophoretic probe sampling and SiC fiber deposition were used to obtain soot samples. The results showed that with the increase of toluene content, the flame height increased and the temperature decreased at the same height. The addition of toluene increased the content of PAHs , which promoted the formation of soot, and increased the number and particle size of soot. At HAB = 30 mm, with the increase of toluene content, the graphitization degree of soot increased, which showed a larger soot fringe length and a smaller fringe tortuosity, and microcrystalline width ( L a) of soot particles increased gradually. It is worth noting that the size of a new structure in the soot deposition is counted for the first time, and it is found that its size is negatively correlated with the fringe length and microcrystalline width of soot.

Mesopore dominated capacitive deionization of N-doped hierarchically porous carbon for water purification

Shoujun Wang,Dezhi Chen,Zhi-Xia Zhang,Yi Hu,Hongying Quan

Under the global shortage of freshwater resources, capacitive deionization (CDI) has attracted widespread attention as an efficient and energy-saving water purification technology. Herein, N-doped hierarchically porous carbons (NPCs) with micro- meso -macropore, excellent specific capacitance (194.75 F g −1 ), large specific surface area (1903.0 m 2 g −1 ), high mesoporous content, and fast ion transport capability were prepared by the pyrolysis of polyacrylonitrile using nano-silica and ZnCl 2 as pore-making agents. As CDI electrode materials for desalination and heavy metal adsorption, the optimized NPC-0.75 electrode delivered a maximum electrosorption capacity of 19.61 mg g −1 at the optimum operating parameters (1.2 V, 10 mL min −1 , 500 mg L -1 NaCl) and an excellent regeneration performance after continuous electrosorption-desorption cycles. The structure–activity relationship analysis indicated that the mesopore dominates the CDI performance of NPCs in water. In addition, NPC-0.75 electrode showed a high removal capacity for Cu 2+ (36.3 mg g −1 ), Cd 2+ (30.02 mg g −1 ) and Pb 2+ (21.5 mg g −1 ) in water. This study provides new insight into the design of high-efficiency porous carbons toward the CDI from water.

Thermoelectric enhancement achieved by Y and La Co-doping in n-type Mg3.2Sb1.5Bi0.5

Yu Jiang,Marhoun Ferhat,Wenhao Fan,Shaoping Chen,Yachao Wang,Jie Chen,Rasha Abdullah Ahmed Al-Yusufi,Chaochao Dun

Additional cation doping is one of the potential strategies to enhance the thermoelectric (TE) performance of Mg 3 Sb 2 -based materials with precise regulation of interaction between cations and the host. In this work, using Mg 3 Sb 1.5 Bi 0.5 as an example, we confirmed that co-doping rare-earth elements with Y and La is capable to simultaneously improve its power factor and suppress the thermal conductivity : Y is an effective n -type dopant to regulate the optimal carrier concentration, while La doping can modulate the band structure and increase the effective mass that related to the improved Seebeck coefficient . A promising power factor of 18.3 μW cm -1 K -2 is obtained after co-doping. Meanwhile, the lattice thermal conductivity is dramatically reduced to 0.39 W m -1 K -1 at 750 K thanks to the extra defect scattering introduced by Y and La. As a result, a peak figure of merit ( zT ) of 1.76 and a competitive average zT of 1.1 among 300–750 K are achieved in Mg 3.2 Y 0.04 La 0.01 Sb 1.5 Bi 0.5 . The synergistic effect stemming from dual-cations doping provides profound insights for controllable host-dopant design and modulation toward high-efficient n-type TE materials .

Constructing Co3O4/La2Ti2O7 p-n Heterojunction for the Enhancement of Photocatalytic Hydrogen Evolution

Haodong Wen,Wenning Zhao,Xiuxun Han

Layered perovskite-type semiconductor La2Ti2O7has attracted lots of attention in photocatalytic hydrogen evolution, due to the suitable energy band position for water splitting, high specific surface area, and excellent physicochemical stability. However, the narrow light absorption range and the low separation efficiency of photogenerated carriers limit its photocatalytic activity. Herein, plate-like La2Ti2O7with uniform crystal morphology was synthesized in molten NaCl salt. A p-n heterojunction was then constructed through the in situ hydrothermal growth of p-type Co3O4nanoparticles on the surface of n-type plate-like La2Ti2O7. The effects of Co3O4loading on photocatalytic hydrogen evolution performance were investigated in detail. The results demonstrate that composite Co3O4/La2Ti2O7possesses much better photocatalytic activity than the pure component. The composite photocatalyst with 1 wt% Co3O4exhibits the highest hydrogen evolution rate of 79.73 μmol·g−1·h−1and a good cycling stability. The photoelectrochemistry characterizations illustrate that the improvement of photocatalytic activity is mainly attributed to both the enhanced light absorption from the Co3O4ornament and the rapid separation of photogenerated electron-hole pairs driven by the built-in electric field close to the p-n heterojunction. The results may provide further insights into the design of high-efficiency La2Ti2O7-based heterojunctions for photocatalytic hydrogen evolution.Keywords:photocatalysis;hydrogen evolution;p-n heterojunction;La2Ti2O7;Co3O4

Novel carboxymethyl chitosan/N-acetylneuraminic acid hydrogel for the protection of Pediococcus pentosaceus

Yuanfei Ge,Jinyong Wu,Min Pang,Dan Hu,Zhongkui Li,Xiangqin Wang,Lijie Sun,Xiangsong Chen,Jianming Yao

In this study, carboxymethyl chitosan (CMCS) and N - acetylneuraminic acid (NeuAc) were used to develop C-NeuAc hydrogels to encapsulate Pediococcus pentosaceus QK-1. The mechanical properties, thermal stability, in vitro degradation, and pH sensitivity of the hydrogel were evaluated. The C-NeuAc concentration required for optimal hydrogel performance was 3% (w/v). Hydrogel swelling behaviour was effectively assessed by Fickian diffusion and Schott’s second-order kinetic models. The hydrogel demonstrated excellent biocompatibility and low in vitro cytotoxicity. An in vitro assay revealed that the viability of Pediococcus pentosaceus QK-1 in C-NeuAc had decreased by only 1.41 log (CFU/ mL) after exposure to simulated acidic gastric fluid. Moreover, the survival rate of the encapsulated and free Pediococcus pentosaceus QK-1 cells were 80.1% and virtually zero, respectively, after passage through the gastrointestinal tract. It was empirically determined that low temperature and freeze-drying were the ideal condition and method to ensure storage longevity of the hydrogel-encapsulated probiotic. Hence, C-NeuAc hydrogel is highly desirable as a food-grade probiotic delivery vehicle.

Co3O4/Co nano-heterostructures embedded in N-doped carbon for lithium-O2 batteries

Lei Ding,Tianyue Huang,Dawei Zhang,Pan Qi,Lihao Zhang,Cong Lin,Hao Luo

Rational design and synthesis of high-performance bifunctional oxygen electrocatalysts with increased effective active sites and facilitated mass/electron transfer are in demand for the lithium-oxygen batteries (LOBs) to overcome the sluggish oxygen reduction/evolution kinetics. Herein, a simple yet effective strategy is proposed by annealing the Prussian blue analog (PBA) precursor under altered calcination conditions to achieve the efficient nano-heterojunction catalysts with optimized active sites. As a result, the obtained porous Co 3 O 4 /Co nano-heterostructures embedded in N-doped graphitized carbon matrix (Co 3 O 4 /Co@NC) exhibit outstanding electrochemical performance with a high specific capacity of 22,156 mA h g −1 at the current density of 100 mA g −1 and excellent stability, obviously superior to the LOBs based on the other single-component catalysts. Systematic investigations suggest that the enhanced electrochemical performance is ascribed to the Co 3 O 4 /Co nano-heterostructure interface and the N-doped porous carbon matrix. This study presents a simple and effective approach for boosting the PBA-derived catalysts with efficient reactivity for various catalytic applications.

Extrusion deposition 3D printed PCL/gel/n-HA composite scaffold for bone regeneration

Chenxin Wang,Jie Liu,Mingyue Lin,Rui Zhang,Yufan Li,Yubao Li,Qin Zou

N-Doped carbon nanotube encapsulated cobalt for efficient oxidative esterification of 5-hydroxymethylfurfural

Linhao Yu,Saravanan Kasipandi,Hong Chen,Yingying Li,Xueli Ma,Zhe Wen,Yongdan Li

Cobalt nanoparticles embedded in graphitic nitrogen-rich carbon nanotubes (Co/GCN) were prepared with a facile method and employed as an efficient catalyst for oxidative esterification of 5-hydroxymethylfurfural (HMF). The introduction of N species to carbon benefits the synergistic effects between the Co nanoparticles and nitrogen-doped carbon nanotube substrate, which modify the surface chemical state of the Co/GCN catalyst and create abundant active sites to improve the HMF conversion. The Co/GCN catalyst carbonized at 800 °C exhibited the best catalytic performance with a 95.8% yield of furan-2,5-dimethylcarboxylate (FDMC) at 98.6% HMF conversion under mild reaction conditions. The effect of acid–base properties of the catalyst on the HMF conversion was investigated and the reaction mechanism of the HMF oxidative esterification was proposed.