Basic Study of High Efficiency Polishing for Surface by Synergistic Effects of Magnetic and Electric Fields

α-Fe2O3, which is an attractive material for supercapacitor electrodes, has been studied to address the issue of low capacitance through structural development and complexation to maximize the use of surface pseudocapacitance. In this study, the limited performance of α-Fe2O3 was greatly improved by optimizing the nanotube structure of α-Fe2O3 and its combination with polyaniline (PANI). α-Fe2O3 nanotubes (α-NT) were fabricated in a form in which the thickness and inner diameter of the tube were controlled by Fe(CO)5 vapor deposition using anodized aluminum oxide as a template. PANI was combined with the prepared α-NT in two forms: PANI@α-NT-a enclosed inside and outside with PANI and PANI@α-NT-b containing PANI only on the inside. In contrast to α-NT, which showed a very low specific capacitance, these two composites showed significantly improved capacitances of 185 Fg−1 for PANI@α-NT-a and 62 Fg−1 for PANI@α-NT-b. In the electrochemical impedance spectroscopy analysis, it was observed that the resistance of charge transfer was minimized in PANI@α-NT-a, and the pseudocapacitance on the entire surface of the α-Fe2O3 nanotubes was utilized with high efficiency through binding and conductivity improvements by PANI. PANI@α-NT-a exhibited a capacitance retention of 36% even when the current density was increased 10-fold, and showed excellent stability of 90.1% over 3000 charge–discharge cycles. This approach of incorporating conducting polymers through well-controlled nanostructures suggests a solution to overcome the limitations of α-Fe2O3 electrode materials and improve performance.

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Vacancy tuned thermoelectric properties and high spin filtering performance in graphene/silicene heterostructures

Scientific Reports ◽

10.1038/s41598-021-94842-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Zainab Gholami ◽

Farhad Khoeini

Keyword(s):

Electric Fields ◽

High Spin ◽

High Efficiency ◽

Practical Applications ◽

External Electric Fields ◽

Ferromagnetic Exchange ◽

High Spin Polarization ◽

Filtering Effect ◽

Spin Switching ◽

Spin Filtering

AbstractThe main contribution of this paper is to study the spin caloritronic effects in defected graphene/silicene nanoribbon (GSNR) junctions. Each step-like GSNR is subjected to the ferromagnetic exchange and local external electric fields, and their responses are determined using the nonequilibrium Green’s function (NEGF) approach. To further study the thermoelectric (TE) properties of the GSNRs, three defect arrangements of divacancies (DVs) are also considered for a larger system, and their responses are re-evaluated. The results demonstrate that the defected GSNRs with the DVs can provide an almost perfect thermal spin filtering effect (SFE), and spin switching. A negative differential thermoelectric resistance (NDTR) effect and high spin polarization efficiency (SPE) larger than 99.99% are obtained. The system with the DV defects can show a large spin-dependent Seebeck coefficient, equal to Ss ⁓ 1.2 mV/K, which is relatively large and acceptable. Appropriate thermal and electronic properties of the GSNRs can also be obtained by tuning up the DV orientation in the device region. Accordingly, the step-like GSNRs can be employed to produce high efficiency spin caloritronic devices with various features in practical applications.

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Synergistic Interfacial and Doping Engineering of Heterostructured NiCo(OH)x-CoyW as an Efficient Alkaline Hydrogen Evolution Electrocatalyst

Nano-Micro Letters ◽

10.1007/s40820-021-00639-x ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Ruopeng Li ◽

Hao Xu ◽

Peixia Yang ◽

Dan Wang ◽

Yun Li ◽

...

Keyword(s):

Hydrogen Evolution ◽

High Efficiency ◽

Low Voltage ◽

Electrochemical Etching ◽

Synergistic Effects ◽

Release Kinetics ◽

Water Electrolysis ◽

Water Dissociation ◽

Practical Applications ◽

Environmentally Friendly Process

AbstractTo achieve high efficiency of water electrolysis to produce hydrogen (H2), developing non-noble metal-based catalysts with considerable performance have been considered as a crucial strategy, which is correlated with both the interphase properties and multi-metal synergistic effects. Herein, as a proof of concept, a delicate NiCo(OH)x-CoyW catalyst with a bush-like heterostructure was realized via gas-template-assisted electrodeposition, followed by an electrochemical etching-growth process, which ensured a high active area and fast gas release kinetics for a superior hydrogen evolution reaction, with an overpotential of 21 and 139 mV at 10 and 500 mA cm−2, respectively. Physical and electrochemical analyses demonstrated that the synergistic effect of the NiCo(OH)x/CoyW heterogeneous interface resulted in favorable electron redistribution and faster electron transfer efficiency. The amorphous NiCo(OH)x strengthened the water dissociation step, and metal phase of CoW provided sufficient sites for moderate H immediate adsorption/H2 desorption. In addition, NiCo(OH)x-CoyW exhibited desirable urea oxidation reaction activity for matching H2 generation with a low voltage of 1.51 V at 50 mA cm−2. More importantly, the synthesis and testing of the NiCo(OH)x-CoyW catalyst in this study were all solar-powered, suggesting a promising environmentally friendly process for practical applications.

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Star Shaped Long Chain Branched Poly (lactic acid) Prepared by Melt Transesterification with Trimethylolpropane Triacrylate and Nano-ZnO

Polymers ◽

10.3390/polym10070796 ◽

2018 ◽

Vol 10 (7) ◽

pp. 796 ◽

Cited By ~ 6

Author(s):

Le Yang ◽

Zaijun Yang ◽

Feng Zhang ◽

Lijin Xie ◽

Zhu Luo ◽

...

Keyword(s):

Lactic Acid ◽

High Efficiency ◽

Synergistic Effects ◽

Transesterification Reaction ◽

Poly Lactic Acid ◽

Cell Diameter ◽

Nano Zno ◽

Melt Strength ◽

Trimethylolpropane Triacrylate ◽

Long Chain

Long chain branched poly (lactic acid) (LCBPLA) was prepared via transesterification between high molecular weight poly (lactic acid) (PLA) and low molar mass monomer trimethylolpropane triacrylate (TMPTA) during melt blending in the presence of zinc oxide nanoparticles (nano-ZnO) as a transesterification accelerant in a torque rheometer. Compared with the traditional processing methods, this novel way is high-efficiency, environmentally friendly, and gel-free. The results revealed that chain restructuring reactions occurred and TMPTA was grafted onto the PLA backbone. The topological structures of LCBPLA were verified and investigated in detail. It was found that the concentration of the accelerants and the sampling occasion had very important roles in the occurrence of branching structures. When the nano-ZnO dosage was 0.4 phr and PLA was sampled at the time corresponding to the reaction peak in the torque curve, PLA exhibited a star-shaped topological structure with a high branching degree which could obviously affect the melt strength, extrusion foaming performances, and crystallization behaviors. Compared with pristine PLA, LCBPLA showed a higher melt strength, smaller cell diameter, and slower crystallization speed owing to the synergistic effects of nano-ZnO and the long chain branches introduced by the transesterification reaction in the system. However, severe degradation of the LCBPLAs would take place under a mixing time that was too long and lots of short linear chains generated due to the excessive transesterification reaction, with a sharp decline in melt strength.

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Research on Key Technology of Electrochemical Sterilization and Physical Application for Circulating Cooling Water

Journal of Physics Conference Series ◽

10.1088/1742-6596/2083/2/022068 ◽

2021 ◽

Vol 2083 (2) ◽

pp. 022068

Author(s):

Xiaohui Wang ◽

Chunyan Song ◽

Xueying Xie ◽

Nan Zhang ◽

Ruiqing Guo ◽

...

Keyword(s):

Electric Fields ◽

Electrode Materials ◽

High Efficiency ◽

Thermal Power ◽

Cooling Water ◽

Environmentally Friendly ◽

Research Progress ◽

Electrode Spacing ◽

Experimental Conditions ◽

Circulating Cooling Water

Abstract As a high-efficiency, low-cost, convenient and environmentally friendly sterilization technology, electrochemical disinfection has developed rapidly in recent years. Electrochemical sterilization is an environmentally friendly sterilization technology. The research progress of this technology in the recent 30 years in sterilization mechanism and electrode materials is summarized. The mechanism of electrochemical sterilization includes the chemical effects of active chlorine, active intermediates, copper or silver ions, and the physical effects of electric fields; the electrode materials used are titanium anode, carbon cathode, and anode. The article combined with electrochemical equipment in a thermal power plant cold open circulating cooling water treatment experiment. Experimental research found that under the conditions of current density of 120A/m2, residence time of 10s, and electrode spacing of 1.8cm, the bactericidal effect can reach 97%. Under certain experimental conditions and a certain period of time, the total number of heterogeneous bacteria in the circulating cooling water after treatment can be effectively inhibited.

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Nanoboxes endow non-noble-metal-based electrocatalysts with high efficiency for overall water splitting

Journal of Materials Chemistry A ◽

10.1039/d0ta10596a ◽

2021 ◽

Author(s):

Cheng Wang ◽

Hongyuan Shang ◽

Hui Xu ◽

Yukou Du

Keyword(s):

Water Splitting ◽

Noble Metal ◽

Active Sites ◽

High Efficiency ◽

Synergistic Effects ◽

Electron Mass ◽

Electronic Effects ◽

Promising Candidate ◽

Surface Active ◽

Electrochemical Water Splitting

Non-noble-metal nanoboxes with abundant surface active sites, facilitated electron/mass transport, favorable synergistic effects and electronic effects, serving as promising candidate materials for boosting electrochemical water splitting.

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Enhanced Microwave Absorption and Electromagnetic Properties of Si-Modified rGO@Fe3O4/PVDF-co-HFP Composites

Materials ◽

10.3390/ma13040933 ◽

2020 ◽

Vol 13 (4) ◽

pp. 933 ◽

Cited By ~ 4

Author(s):

Yuexuan Li ◽

Yugang Duan ◽

Chengmeng Wang

Keyword(s):

Microwave Absorption ◽

Reflection Loss ◽

High Efficiency ◽

Vinylidene Fluoride ◽

Synergistic Effects ◽

Electromagnetic Properties ◽

Absorption Mechanism ◽

Simple Method ◽

Absorption Frequency ◽

Enhanced Absorption

Graphene has been regarded as one of the most promising two-dimensional nanomaterials. Even so, graphene was still faced with several key issues such as impedance mismatching and narrow bandwidth, which have hindered the practical applications of graphene-based nanocomposites in the field of microwave absorption materials. Herein, a series of Si-modified rGO@Fe3O4 composites were investigated and fabricated by a simple method. On one hand, the degree of defects in graphene carbon could be tuned by different silane coupling reagents, which were beneficial to enhancing the dielectric loss. On the other hand, the spherical Fe3O4 nanoparticles provided the magnetic loss resonance, which contributed to controlling the impedance matching. Subsequently, the electromagnetic absorption (EMA) properties of Si-modified rGO@Fe3O4 composites with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) were investigated in this work. As a result, the Si(2)-rGO@Fe3O4/PVDF-co-HFP composite exhibited the excellent EMA performance in the range of 2–18 GHz. The maximum reflection loss (RLmax) reached −32.1 dB at 3.68 GHz at the thickness of 7 mm and the effective absorption frequency bandwidth for reflection loss (RL) below −10 dB was 4.8 GHz at the thickness of 2 mm. Furthermore, the enhanced absorption mechanism revealed that the high-efficiency absorption performance of Si(2)-rGO@Fe3O4/PVDF-co-HFP composite was attributed to the interference absorption (quarter-wave matching model) and the synergistic effects between Si(2)-rGO@Fe3O4 and PVDF-co-HFP. This work provides a potential strategy for the fabrication of the high-performance EMA materials.

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Electrospinning Ag-TiO2 Nanorod-Loaded Air Treatment Filters and Their Applications in Air Purification

Molecules ◽

10.3390/molecules25153369 ◽

2020 ◽

Vol 25 (15) ◽

pp. 3369

Author(s):

Shan-Jiang Wang ◽

Xiao-Yang Zhang ◽

Dan Su ◽

Yun-Fan Wang ◽

Chun-Meng Qian ◽

...

Keyword(s):

Organic Pollutants ◽

High Efficiency ◽

Synergistic Effects ◽

Cost Effective ◽

Electrospinning Process ◽

Advanced Materials ◽

Superior Performance ◽

Efficient Treatment ◽

Air Treatment ◽

Tio2 Nanorod

The efficient treatment of the problem of air pollution is a practical issue related to human health. The development of multi-functional air treatment filters, which can remove various kinds of pollutants, including particulate matter (PM) and organic gases, is a tireless pursuit aiming to address the actual needs of humans. Advanced materials and nano-manufacturing technology have brought about the opportunity to change conventional air filters for practical demands, with the aim of achieving the high-efficiency utilization of photons, a strong catalytic ability, and the synergetic degradation of multi-pollutants. In this work, visible-responding photocatalytic air treatment filters were prepared and combined with a fast and cost-effective electrospinning process. Firstly, we synthesized Ag-loaded TiO2 nanorod composites with a controlled size and number of loaded Ag nanoparticles. Then, multi-functional air treatment filters were designed by loading catalysts on electrospinning nanofibers combined with a programmable brush. We found that such Ag-TiO2 nanorod composite-loaded nanofibers displayed prominent PM filtration (~90%) and the degradation of organic pollutants (above 90%). The superior performance of purification could be demonstrated in two aspects. One was the improvement of the adsorption of pollutants derived from the increase of the specific surface area after the loading of catalysts, and the other was the plasmonic hot carriers, which induced a broadening of the optical absorption in the visible light range, meaning that many more photons were utilized effectively. The designed air treatment filters with synergistic effects for eliminating both PM and organic pollutants have promising potential for the future design and application of novel air treatment devices.

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Low-Temperature High-Efficiency Preparation of TiB2 Micro-Platelets via Boro/Carbothermal Reduction in Microwave Heated Molten Salt

Materials ◽

10.3390/ma12162555 ◽

2019 ◽

Vol 12 (16) ◽

pp. 2555 ◽

Cited By ~ 2

Author(s):

Jie Liu ◽

Jianghao Liu ◽

Yuan Zeng ◽

Haijun Zhang ◽

Zhi Li

Keyword(s):

Low Temperature ◽

Molten Salt ◽

Carbothermal Reduction ◽

High Efficiency ◽

Raw Materials ◽

Synergistic Effects ◽

Synthesis Conditions ◽

Crystalline Nature ◽

Boron Carbide B4c ◽

Hexagonal Platelet

A molten-salt and microwave co-facilitated boro/carbothermal reduction methodology was developed for low temperature high-efficiency synthesis of TiB2 powders. By using relatively inexpensive titanium oxide (TiO2), boron carbide (B4C) and amorphous carbon (C) as raw materials, single-phase TiB2 powders were prepared after 60 min at as low as 1150 °C or after only 20 min at 1200 °C. Such synthesis conditions were remarkably milder than those required by the conventional reduction routes using the identical reducing agent. As-synthesized TiB2 powders exhibited single-crystalline nature and well-grown hexagonal-platelet-like morphology. The achievement of low temperature high-efficiency preparation of high-quality TiB2 microplatelets in the present work was mainly attributable to the synergistic effects of molten-salt medium and microwave heating.

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One-Step Hydrothermal Synthesis of Yellow and Green Emitting Silicon Quantum Dots with Synergistic Effect

Nanomaterials ◽

10.3390/nano9030466 ◽

2019 ◽

Vol 9 (3) ◽

pp. 466

Author(s):

Zhixia Zhang ◽

Chunjin Wei ◽

Wenting Ma ◽

Jun Li ◽

Xincai Xiao ◽

...

Keyword(s):

Quantum Dots ◽

Synergistic Effect ◽

High Efficiency ◽

Synergistic Effects ◽

Biomedical Science ◽

Future Application ◽

Quantum Yields ◽

Silicon Quantum Dots ◽

Long Wavelength ◽

One Step

The concept of synergistic effects has been widely applied in many scientific fields such as in biomedical science and material chemistry, and has further attracted interest in the fields of both synthesis and application of nanomaterials. In this paper, we report the synthesis of long-wavelength emitting silicon quantum dots based on a one-step hydrothermal route with catechol (CC) and sodium citrate (Na-citrate) as a reducing agent pair, and N-[3-(trimethoxysilyl)propyl]ethylenediamine (DAMO) as silicon source. By controlling the reaction time, yellow-emitting silicon quantum dots and green-emitting silicon quantum dots were synthesized with quantum yields (QYs) of 29.4% and 38.3% respectively. The as-prepared silicon quantum dots were characterized by fluorescence (PL) spectrum, UV–visible spectrum, high resolution transmission electron microscope (HRTEM), Fourier transform infrared (FT-IR) spectrometry energy dispersive spectroscopy (EDS), and Zeta potential. With the aid of these methods, this paper further discussed how the optical performance and surface characteristics of the prepared quantum dots (QDs) influence the fluorescence mechanism. Meanwhile, the cell toxicity of the silicon quantum dots was tested by the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium (MTT) bromide method, and its potential as a fluorescence ink explored. The silicon quantum dots exhibit a red-shift phenomenon in their fluorescence peak due to the participation of the carbonyl group during the synthesis. The high-efficiency and stable photoluminescence of the long-wavelength emitting silicon quantum dots prepared through a synergistic effect is of great value in their future application as novel optical materials in bioimaging, LED, and materials detection.

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