Strong Interaction Force Research Articles

Investigating the effect of Pr doping BiFeO3 on the microwave absorption and magnetic properties

Bi1-xPrxFeO3 material with perovskite structure was prepared using organic tartaric acid-assisted sol–gel self-propagating combustion method to obtain high-efficiency microwave absorption materials. The influence of the introduction of Pr on dielectric properties and permeability was further studied. After 15% Pr introduced, the lowest reflection absorption loss reaches –32.34 dB, but the absorption bandwidth is only 2.25 GHz. When Pr is 5%, the lowest reflection absorption loss value of −27.31 dB is obtained, and the effective bandwidth which below −10 dB is 3.41 GHz. The structural changes in the process of Pr replacing Bi were analyzed to explore the properties of BPFO perovskite. The influence of strong interaction force, residual magnetization, and natural resonance of ceramic nanoparticles on microwave absorption performance was explored. This work supplies a reliable candidate material for making up electromagnetic attenuation ceramic materials with excellent properties.

Effect of microcosmic regulation of unit cells bonding on microwave absorption properties of perovskite structure GdFeO3

GdFe1-xNixO3 material with perovskite structure was prepared using organic monohydrated citric acid-assisted sol–gel self-propagating combustion method to obtain high-efficiency microwave absorption material with thin thickness and wide effective absorption band. The influence of the introduction of Ni on dielectric properties and permeability was further studied. Experimental results show that with the introduction of 10% Ni, the lowest reflection absorption loss value of -49.5 dB is obtained, but the absorption bandwidth is only 0.89 GHz. When Ni is 15%, the lowest reflection absorption loss value of -38.8 dB is obtained, and the effective bandwidth (< -10 dB) is 5.32 GHz. The structure of GdFe1-xNixO3 perovskite was analyzed to explore structural changes in the process of Ni replacing Fe. The influence of strong interaction force, residual magnetization, and natural resonance of ceramic nanoparticles on microwave absorption performance was explored. This work provides a reliable candidate material for the synthesis of electromagnetic attenuation ceramic materials with excellent properties.

Wax Separated Effectively from Fischer-Tropsch Wax Residue by Solvent Desorption: Thermodynamic and Kinetic Analysis

The separation and recycling of effective resources in Fischer-Tropsch wax residue (FTWR) are urgent because of the environmental hazards and energy waste they bring. In this study, organic solvents are used to separate recyclable resources from FTWR efficiently, achieving the goals of “Energy Recycle” and “Fisher-Tropsch Wax Residue Treatment”. The response surface methodology (RSM) response surface analysis model accurately evaluates the relationship among temperature, residence time, liquid–solid ratio, and desorption rate and obtains the best process parameters. The results show that the product yield can reach 82.28% under the conditions of 80 °C, 4 h, and the liquid–solid ratio of 24.4 mL/g. Through the kinetic analysis of the desorption process of FTWR, the results show that the desorption process conforms to the pseudo second-order kinetic model and the internal diffusion model. The thermodynamic function results showed that there were not only van der Waals forces in the desorption process, but other strong interaction forces such as hydrogen bonds. In addition, Langmuir, Freundlich, and BET equations are used to describe the desorption equilibrium. Scanning electron microscopy (SEM) were used to analyze the pore structure of FTWR during desorption. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Gas chromatography-mass spectrometer (GC-MS) analysis confirmed that the desorption product’s main component was hydrocarbons (50.38 wt%). Furthermore, naphthenic (22.95 wt%), primary alcohol (11.62 wt%), esters (8.7 wt%), and aromatic hydrocarbons (6.35 wt%) compounds were found and can be further purified and applied to other industrial fields. This study shows that using petroleum ether to separate and recover clean resources from Fischer-Tropsch wax residue is feasible and efficient and has potential industrial application prospects.

Boosting photogenerated carriers for organic pollutant degradation via in-situ constructing atom-to-atom TiO2/ZrTiO4 heterointerface

Constructing favorable heterointerface to facilitate photogenerated carrier transport is an effective way to improve the photocatalytic activities of semiconductor catalysts. However, the fabrication of atomic-level interface remains a challenge due to the difficulties in constructing intimate interface contact. Herein, a unique atom-to-atom TiO2/ZrTiO4 heterointerface with the potential formation of Ti–O–Ti(Zr) bonds between TiO2 and ZrTiO4 was constructed through the in-situ formation of the two components using a one-step sol-gel method. The resulting photocatalyst exhibited superior photocatalytic activity and high stability, i.e., about 97% of Rhodamine B was degraded after visible light irradiation for 90 min for three consecutive photodegradation cycles. By further analyses such as refined X-ray diffractometer (XRD), X-ray photoelectron spectrometer (XPS), Raman microscope (Raman), photoluminescence (PL), and photoelectrochemical spectra (TP and EIS), it revealed that the atom-to-atom heterointerface of TiO2/ZrTiO4 with stronger interaction forces would greatly accelerate the charge separation as well as provide generous defect sites, boosting the number of photogenerated carriers available at reaction sites, thus contribute to the improvement of photocatalytic performance. The present work demonstrates a new approach of in-situ construction for interface engineering TiO2 based catalyst, providing design guidelines for heterointerface photocatalytic structures.

Polybenzimidazole/cerium dioxide/graphitic carbon nitride nanosheets for high performance and durable high temperature proton exchange membranes

A novel membrane was fabricated from polybenzimidazole (m-PBI) and cerium dioxide/graphitic carbon nitride nanosheets (m-PBI-X wt%/CeO2/g-C3N4) in order to achieve long-term durability and excellent performance as high temperature proton exchange membrane (HT-PEM) for fuel cells (FCs). The CeO2 nanoparticles was employed to disperse 2D graphitic carbon nitride nanosheets (g-C3N4) in the PBI solution as confirmed by SEM, and also to scavenge the possible hydroxyl radicals when the membrane is operated in the fuel cell device. Unlike to other composite membrane in which the introduction of nanoparticles generally resulted in the sacrificing of mechanical properties, the well dispersed g-C3N4 and CeO2 in PBI membrane induced the excellent mechanical properties. Moreover, the abundant nitrogen atom in g-C3N4 showed strong interaction force with phosphoric acid as confirmed by theoretical calculation. Thus, high proton conductivities of composite membrane have been observed. Thus, the m-PBI/1% CeO2/g-C3N4 composite membrane showed the highest peak power density of 540 mW cm−2 at 160 °C, which is higher than that of the pristine m-PBI membrane (359.31 mW cm−2) under the same testing condition. Most importantly, the durability test demonstrated that the voltage has no obvious attenuation during the 200 h test indicating its excellent stability under the fuel cell device environment at 160 °C. These results indicated that the m-PBI-X wt%/CeO2/g-C3N4 composite membranes was a promising membrane for the application of HT-PEMFCs.

MoC quantum dots modified by CeO2 dispersed in ultra-thin carbon films for efficient photocatalytic hydrogen evolution

MoC quantum dots are dispersed in a carbon film by the temperature-programmed method. The hybrid catalyst is obtained by the mixed solution method, and the hybrid catalyst is optimized by adjusting the content of CeO2 to obtain the composite catalyst 15%-COMCC with the best photocatalytic hydrogen evolution activity. SEM and TEM show that there is an intimate interface contact between CeO2 and MoC-QDs/C, which provides the basis for smooth electron transfer. It is proved by XPS that there is a strong interaction force between the catalysts, which provides a evidence for electron transfer between semiconductors. It is proved by electrochemistry that the introduction of CeO2 can effectively reduce the hydrogen evolution potential and provide powerful conditions for the hydrogen production of the hybrid catalyst. The carbon film has excellent conductivity, can effectively suppresses the recombination of photo-generated carriers, and accelerate the separation of carriers between the interfaces. MoC quantum dots with high dispersibility embedded in the carbon film provide a lot of active sites for photocatalytic hydrogen production. This research provides an effective strategy for the application of ultra-thin carbon film in photocatalytic hydrogen evolution, the loading of quantum dots, and the design and synthesis of non-noble metals.

Magnetic Solid-Phase Extraction of Drugs and Pesticides from Human Plasma Using COOH-mMWCNTs.

Carbon nanotubes (CNTs) are useful for extracting chemical compounds due to their properties, such as surface area and the potential for chemical modification. Especially the formation of CNTs with carboxylic acid functional group makes them disperse in water-based samples and have strong interaction forces with cationizable analytes. Based on these features, carboxylic acid functionalized multi-walled CNTs (COOH-MWCNTs) have been used as extraction sorbents. CNT can also be gathered using an external magnet by forming complex with iron oxide (Fe3O4) magnetic nanoparticles (MNPs). In this study, COOH-MWCNTs with MNPs were subjected to magnetic solid-phase extraction (mSPE) in order to extract the targeted substances such as diphenhydramine, doxylamine, tramadol, escitalopram, zolpidem, diphenamid, paclobutrazol, hexaconazole, cyproconazole and mepronil from human plasma samples. The following five factors were optimized: (i) the ratio of COOH-MWCNTs to MNPs as a sorbent from 1:1 to 1:4; (ii) sorbent amount starting from 12.5 to 75%; (iii) sample pH tested pH2 to pH10 with 1N hydrochloride and 1N sodium hydroxide; (iv) agitating time from 0 to 4min and (v) elution solvent. Limit of detection of 10 targeted substances in human plasma were in the range of 0.1-0.4mg/L. The recovery of targeted substances (except diphenamid) in human plasma was 73.06-110.28% for intra-day and 83.00-107.70% for inter-day and the precision (relative standard deviation, %) in human plasma was 0.3-13.3% for intra-day and 2.9-15.6% for inter-day. The method was applied to nine authentic biological samples from overdose patients in the emergency room of Chungnam National University Hospital. The performance of mSPE was compared with the liquid-liquid extraction method using ethyl acetate. The results showed that the newly developed method in this study can be used for screening analysis in forensic and clinical toxicology.

Parthenocissus-inspired, strongly adhesive, efficiently self-healing polymers for energetic adhesive applications

Strong interaction force improves the mechanical properties of energetic composites, and plentiful dynamic H-bonds endue excellent crack-healing performance.

Functionalized graphene oxide nanosheets with unique three-in-one properties for efficient and tunable antibacterial applications

Developing antibiotics-independent antibacterial agents is of great importance since antibiotic therapy faces great challenges from drug resistance. Graphene oxide (GO) is a promising agent due to its natural antibacterial mechanisms, such as sharp edge-mediated cutting effect. However, the antibacterial activity of GO is limited by its negative charge and low photothermal effect. Herein, the amino-functionalized GO nanosheets (AGO) with unique three-in-one properties were synthesized. Three essential properties (positive charge, strong photothermal effect, and natural cutting effect) were integrated into AGO. The positive charge (30 mV) rendered AGO a strong interaction force with model pathogen Streptococcus mutans (330 nN). The natural cutting effect of 100 µg·mL−1 AGO caused 27% loss of bacterial viability after incubation for 30 min. Most importantly, upon the near-infrared irradiation for just 5 min, the three-in-one properties of AGO caused 98% viability loss. In conclusion, the short irradiation period and the tunable antibacterial activity confer the three-in-one AGO a great potential for clinical use.

Mixed matrix membranes for rubidium-dependent recognition and separation: A synergistic recombination design based on electrostatic interactions

Exposure and distribution of recognition sites are critical for membrane separation materials to enhance adsorption and separation efficiency toward rubidium ion. Herein, we prepared the rubidium (Rb) ion separation membranes (Rb-ISMs) through a delayed phase inversion method taking advantage of the different polarities between ethanol and water. Fabrication process was conducted through immersion of a poly (vinylidene fluoride)/graphene oxide (PVDF/GO) casting solution into coagulating bath containing 18-crown-6 (18C6) grafted mesoporous silica, ethanol and water. After phase inversion process, the as-prepared adsorbent materials were immobilized on membrane surface by strong electrostatic interaction force. The method could effectively avoid the embedding and aggregation recognition sites, and the coagulating bath only required the ethanol and water that was relatively healthy and environmental. The Rb-ISMs prepared at optimal conditions showed enhanced rebinding capacity (49.344 mg g−1) towards Rb±, with a superior rebinding selectivity (11.8, 6.82, 9.08 for Rb±/Ca2+, Rb±/Cs±, Rb±/Mg2+, respectively). Importantly, Rb-ISMs showed remarkable perm-selectivity and regeneration performance, which further demonstrated its potentials in the rapid and effective separation field of Rb ions.

Anthraquinone Covalently Modified Carbon Nanotubes for Efficient and Steady Electrocatalytic H2O2 Generation

Anthraquinone(AQ) modified carbon materials could be endowed with significantly improved oxygen reduction reaction(ORR) activity. However, the application of these materials in the generation of hydrogen peroxide (H2O2) has been rarely investigated. For this motivation, AQ covalently modified carbon nanotube(AQ-CNT) was purposely synthesized for H2O2 generation. It was found that the cumulative H2O2 concentration reached up to 187.18 mg/(Lh) over AQ(40)-CNT catalyst, nearly 2.0 times higher than that over CNT, and being superior to those over most carbon materials reported. The enhanced activity stemmed from the improved mass transfer efficiency of oxygen and the enhanced electrocatalytic activity. Noteworthily, the AQ(40)-CNT material exhibited satisfactory stability for H2O2 generation, which was ascribed to the strong interaction force of C-N covalent bond. The present work could provide a vital idea for designing electrode material with simultaneously improved activity and stability for H2O2 generation.

Ultrasonic and Thermophysical Studies of Ethylene Glycol Nanofluids Containing Titania Nanoparticles and Their Heat Transfer Enhancements

In the present investigation, TiO2 nanostructures were synthesised via a simple sol-gel technique and characterised with X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX), high-resolution transmission electron microscopy (HR-TEM) and ultraviolet-visible (UV-vis) spectroscopy. The temperature and concentration dependence of thermal conductivity enhancement (TCE) and ultrasonic velocity have been explored in ethylene glycol-based TiO2 nanofluids. The obtained results showed 24% enhancement in thermal conductivity at higher temperature (80°C) of the base fluid ethylene glycol by adding 1.0 wt% of TiO2 nanoparticles. The behaviour of TCE and ultrasonic velocity with temperature in prepared nanofluids has been explained with the help of existing phenomena. The increase in ultrasonic velocity in ethylene glycol with TiO2 nanoparticles shows that a strong cohesive interaction force arises among the nanoparticles and base fluid. These results divulge that TiO2 nanoparticles can be considered for applications in next-generation heat transfer in nanofluids.

Zr(OH)4/GO Nanocomposite for the Degradation of Nerve Agent Soman (GD) in High-Humidity Environments.

Zirconium hydroxide, Zr(OH)4 is known to be highly effective for the degradation of chemical nerve agents. Due to the strong interaction force between Zr(OH)4 and the adsorbed water, however, Zr(OH)4 rapidly loses its activity for nerve agents under high-humidity environments, limiting real-world applications. Here, we report a nanocomposite material of Zr(OH)4 and graphene oxide (GO) which showed enhanced stability in humid environments. Zr(OH)4/GO nanocomposite was prepared via a dropwise method, resulting in a well-dispersed and embedded GO in Zr(OH)4 nanocomposite. The nitrogen (N2) isotherm analysis showed that the pore structure of Zr(OH)4/GO nanocomposite is heterogeneous, and its meso-porosity increased from 0.050 to 0.251 cm3/g, compared with pristine Zr(OH)4 prepared. Notably, the composite material showed a better performance for nerve agent soman (GD) degradation hydrolysis under high-humidity air conditions (80% relative humidity) and even in aqueous solution. The soman (GD) degradation by the nanocomposite follows the catalytic reaction with a first-order half-life of 60 min. Water adsorption isotherm analysis and diffuse reflectance infrared Fourier transform (DRIFT) spectra provide direct evidence that the interaction between Zr(OH)4 and the adsorbed water is reduced in Zr(OH)4/GO nanocomposite, indicating that the active sites of Zr(OH)4 for the soman (GD) degradation, such as surface hydroxyl groups are almost available even in high-humidity environments.

Influence of substrate on ultrafast water transport property of multilayer graphene coatings

The ultrafast water transport in graphene nanoplatelets (GNPs) coating is attributed to the low friction passages formed by pristine graphene and the hydrophilic functional groups which provide a strong interaction force to the water molecules. Here, we examine the influence of the supporting substrate on the ultrafast water transport property of multilayer graphene coatings experimentally and by computational modelling. Thermally cured GNPs manifesting ultrafast water permeation are coated on different substrate materials, namely aluminium, copper, iron and glass. The physical and chemical structures of the GNPs coatings which are affected by the substrate materials are characterized using various spectroscopy techniques. Experimentally, the water permeation and absorption tests evidence the significant influence of the substrate on the rapid water permeation property of GNPs-coating. The water transport rates of the GNPs coatings correspond to the wettability and the free surface energy of their substrates where the most hydrophilic substrate induces the highest water transport rate. In addition, we conduct molecular dynamics (MD) simulations to investigate the transport rate of water molecules through multilayer GNPs adjacent to different substrate materials. The MD simulations results agree well with the experimental results inferring the strong influence of the substrate materials on the fast water transport of GNPs. Therefore, selection of substrate has to be taken into consideration when the GNPs-coating is placed into applications.

A Multi-Scale Modeling of Confined Fluid: from Nanopore to Unconventional Reservoir Simulation

Tight oil and shale gas reservoirs have a significant part of their pore volume occupied by micro (below 2 nm) and mesopores (between 2 and 50 nm). This kind of environment creates strong interaction forces in the confined fluid with pore walls and then changes dramatically the fluid phase behavior. An important work has therefore to be done on thermodynamic modeling of the confined fluid and on developing upscaling methodology of the pore size distribution for large scale reservoir simulations. Firstly, the comparison between molecular simulation results and commonly used modified equation of state (EOS) in the literature highlighted the model of flash with capillary pressure and critical temperature and pressure shift as the best one to model confined fluid behavior. Then, fine grid matrix/fracture simulations have been built and performed for different pore size distributions. The study has shown that the pore size distribution has an important impact on reservoir production and this impact is highly dependent on the volume fraction of nanopores inside the matrix. Afterwards, coarse grid upscaling models have then been performed on the same synthetic case and compared to the reference fine grid results. The commonly used upscaling methodology of dual porosity model with average pore radius for the pore size distribution is unable to match the fine grid results. A new triple porosity model considering fracture, small pores and large pores with their own capillary pressure and EOS, together with MINC (Multiple Interacting Continua) approach, has shown very good agreement with the reference fine grid results. Finally a large scale stimulated reservoir volume with different pore size distribution inside the matrix has been built using the upscaling method developed here.

Efficient strain modulation of 2D materials via polymer encapsulation

Strain engineering is a promising method to manipulate the electronic and optical properties of two-dimensional (2D) materials. However, with weak van der Waals interaction, severe slippage between 2D material and substrate could dominate the bending or stretching processes, leading to inefficiency strain transfer. To overcome this limitation, we report a simple strain engineering method by encapsulating the monolayer 2D material in the flexible PVA substrate through spin-coating approach. The strong interaction force between spin-coated PVA and 2D material ensures the mechanical strain can be effectively transferred with negligible slippage or decoupling. By applying uniaxial strain to monolayer MoS2, we observe a higher bandgap modulation up to ~300 meV and a highest modulation rate of ~136 meV/%, which is approximate two times improvement compared to previous results achieved. Moreover, this simple strategy could be well extended to other 2D materials such as WS2 or WSe2, leading to enhanced bandgap modulation.

Elucidation of Colloid Performances of Thermosensitive In Situ–Forming Ophthalmic Gel Formed by Poloxamer 407 for Loading Drugs

The herein work elucidated colloid performances of thermosensitive in situ–forming ophthalmic gel established by poloxamer 407 (F127), mainly including facile and simple methods (load-bearing method, tilting plate method, and eye simulation method) to analyze and evaluate F127 gel and intensively addressed capacity of F127 gel for loading drugs. The results demonstrated that the poorly water-soluble berberine hydrochloride improved entangled intensity of F127 and therefore reduced the sol dynamic rate, which contributed to lower gelation temperature and enhancement of cornea adhesion, further lowering the rate of gel corrosion together with drug release. Importantly, the addition of hydroxy propyl methyl cellulose (HPMC) K15M contributed to stronger gel strength because strong interaction forces were formed between HPMC K15M and F127 when the molecular chain segments of HPMC K15M interspersed among F127 network. All the aforementioned results provide valuable instruction for designing and evaluating thermosensitive in situ–forming ophthalmic gel.

Towards high-volumetric performance of Na/Li-ion batteries: a better anode material with molybdenum pentachloride–graphite intercalation compounds (MoCl5–GICs)

MoCl5–GICs are demonstrated as advanced anodes for simultaneously achieving high volumetric capacity and long cycle life in Na-ion and Li-ion batteries, owing to a strong charge transfer chemical doping effect and strong interaction force between MoCl5 and graphite layers.

Efficient removal of methyl orange by a flower-like TiO2/MIL-101(Cr) composite nanomaterial.

Nano-scale MOF composite materials prepared by combining inorganic semiconductors with controllable pore structures and functional active sites for the effective removal of organic dyes will exhibit more excellent adsorption activity. In this paper, MIL-101(Cr) was used as a carrier and two-step hydrothermal methods were successfully used to prepare flower-like TiO2/MIL-101(Cr) composite nano-adsorbents with different sizes. The results of XRD, SEM, XPS and other characterization methods showed that when the molar ratio of Ti : Cr was 0.2 : 1, the composite nano-adsorbent exhibited better adsorption performance and removal efficiency for methyl orange (MO) in aqueous solution. By assembling TiO2 on MIL-101(Cr), Ti replaced part of Cr, and the positively-charged TiO2/MIL-101(Cr) nanocomposite and negatively-charged MO in aqueous solution formed a strong interaction force. In addition, the π-π packing interactions of the benzene ring of MIL-101(Cr) and the electrostatic force between TiO2 and MIL-101(Cr) also enhanced the performance and adsorption efficiency of the adsorbent to a certain extent. The BET results showed that the large specific surface area and average pore diameter of the TiO2/MIL-101(Cr) nanocomposites effectively improved the adsorption performance of the composites. The results showed that the MO removal efficiency of 20% TiO2/MIL-101(Cr) can reach 93.03% at 80 min. But when 20% TiO2/MIL-101(Cr) was used to adsorb 70 mg·L-1 MO, the experimental maximum adsorption capacity was 242.02 mg·g-1.

Efficient Debundling of Few-Walled Carbon Nanotubes by Wrapping with Donor-Acceptor Polymers for Improving Thermoelectric Properties.

Organic thermoelectric (TE) materials have great potential as sustainable energy sources for powering flexible and wearable electronic devices via harvesting of human body heat. Recent advances in soluble conjugated polymer/carbon nanotube (CNT) composites have facilitated achievement of high TE power factors. However, the effects of conjugated polymers on the debundling and electrical percolation of CNTs and on the TE properties of their composites are not yet fully understood. Herein, we introduce a novel type of polymer/CNT composite composed of a donor-acceptor (D-A)-type polymer and few-walled CNTs (FWCNTs). Three kinds of D-A polymers are employed to disperse FWCNTs, and the photophysical, morphological, and TE properties of the resulting polymer/FWCNT composites are compared with those of composites composed of FWCNTs dispersed with conventional donor-only poly(3-hexylthiophene). The results reveal that the strong intermolecular interaction forces and high backbone planarity of the D-A polymers facilitate effective debundling of FWCNTs, which results in much smaller bundle sizes. Consequently, the D-A polymer/FWCNT composite films show superior electrical percolation and TE performances with improved power factors of up to 459 μW/mK2. Finally, we demonstrate the feasibility of the D-A polymer/FWCNT composites for use in the fabrication of a flexible TE generator, which shows a maximum power output of 210 nW at a temperature gradient of 20 K.