Super Performance Research Articles

Nickel iron carbonate hydroxide hydrate decorated with CeOx for highly efficient oxygen evolution reaction

Highly active, durable, and inexpensive nanostructured catalysts are crucial for achieving efficiently and economically electrochemical water splitting. In recent years, the introduction of cerium (Ce) into electrocatalysts is an effective way to improve the performance of oxygen evolution reaction (OER). Herein, we report a cerium oxide deposited nickel iron carbonate hydroxide hydrate (NiFeCH(Ce)) on the carbon fiber paper through two-step hydrothermal/electrodeposition approach. The NiFeCH(Ce) not only exhibits a remarkably improved OER performance with an overpotential of 252 mV at a current density of 100 mA cm−2, but also possesses a small Tafel slope of 59 mV dec−1, the both values superior to the most non-noblemetal-based OER electrocatalysts reported. X-ray photoelectron spectroscopy analysis shows that the super OER electrocatalysis performance of the NiFeCH(Ce) was related intensely with the introduction of Ce ions, which not only richer surface defects and higher oxygen adsorption capacity, but also provide more effective charge and mass transfer between intermediates and catalysts, making a great contribution to the OER enhancement.

Laser sintering method induced c-axis growth of Mg0.2Zn0.8O nano-film for ultraviolet photodetector

Ultraviolet (UV) photodetector was fabricated on Mg0.2Zn0.8O nano-rod film synthesized by laser sintering method. The X-ray diffraction pattern shows that Mg0.2Zn0.8O film grows along c-axis orientation with a wurtzite structure. Absorption edge locates at 351 nm and the band gap is determined to − 3.53 eV. The UV photodetector has a response peak at − 328 nm corresponding to a saturation responsivity of 0.196 A·W−1 at 20 V bias. The UV/visible rejection ratio of the photodetector is close to 2 orders of magnitude. The super perfect photo-electronic performance of the detector illustrates that laser sintering method has a vital advantage to synthesized Mg0.2Zn0.8O nano-film for UV photodetector.

Stable interface Co3O4-coated LiNi0.5Mn1.5O4 for lithium-ion batteries

The spinel LiNi0.5Mn1.5O4 (LNMO) has received much attention as a cathode material in high energy density lithium-ion battery thanks to its high working voltage. It is recognized that its interface instability issues, especially for the Fd-3m phase with superior conductivity, Co3O4 is employed as an interface coating to stabilize the surface structure of LNMO. A series of test results demonstrated that the side-reaction between LNMO and electrolyte interface is greatly reduced, and as a result, the formation of cathode electrolyte interfacial (CEI) film is inhibited, and the structural change and manganese dissolution are also alleviated. The modified LNMO shows super rate performance and excellent cycle retention. Specifically, the LNMO material coated with 0.8 wt% Co presents a discharge capacity of 120 mA h g−1 at a rate of 10 C with a capacity retention rate of 95.8% after 300 cycles.

Regenerated WO2.72 nanowires with superb fast and selective adsorption for cationic dye: Kinetics, isotherm, thermodynamics, mechanism.

Hydrothermally prepared nonstoichiometry tungsten oxide (WO2.72) nanowires possess super selective adsorption performance for methylene blue (MB). The effects of dye concentration, contact time, pH and temperature on the adsorption properties of WO2.72 were investigated. The experimental results indicated that WO2.72 nanowires have a high adsorption capacity (547.32 mg/g) under neutral pH and a fast adsorption rate (adsorbing 100% within 6 min) for MB dye. The kinetic data showed good correlation coefficient (R2 > 0.99) for the pseudo-second-order. The equilibrium data suggesting the monolayer coverage of adsorbate as it fits well with the Langmuir isotherm model (R2 > 0.99). The energy functions of chemical thermodynamics revealed the adsorbate transport across the phase boundary is spontaneous and exothermic. Electrostatic absorption was proposed as the main adsorption mechanisms. Calcination treatment was utilized to decompose MB adsorbed on WO2.72 and regenerate WO2.72. The adsorption efficiency of WO2.72 nanowires can still reach 86.54% after recycling five times, which indicated that as-obtained WO2.72 nanowires are a very promising high-efficiency adsorbent for practical purification of dyeing waste water.

Halbach array assisted assembly of orderly aligned nickel nanowire networks as transparent conductive films

The aspect ratio and arrangement of nanowires play an important role in achieving excellent optoelectronic performance for metal nanowire-based transparent conductive films (TCFs). However, limited to the technology and material properties, studies are always focused on only one of the issues. Here, a novel strategy for manipulating the relative aspect ratio and arrangement of nickel nanowires (NiNWs) at nanoscale by Halbach array assisted assembly technology is introduced. Head-to-tail nickel nanowire chains as large as hundreds of micrometers are formed as a result of the dipole–dipole interactions of wire–wire. The arrangement of nickel nanowires can be preciously controlled by layer-by-layer deposition. Notably, the alignment create a significant improvement on the optoelectronic performance of nickel nanowire TCFs. The optimized orderly aligned NiNWs TCFs demonstrate super optoelectronic performance (90 Ω sq−1, 86%) than disordered NiNW TCFs (200 Ω sq−1, 80%). Moreover, NiNW-based TCFs exhibit outstanding long-term oxidation stability at 80 °C over 30 d as well as high-temperature oxidization stability even up to 300 °C, that is the most stable metal nanowire-based TCFs in air as far as we know. The low-cost, good optoelectronic performance and excellent oxidation resistance of aligned NiNWs will make them as attractive alternatives to silver nanowires for TCFs application.

Evaluation, of the bimetallic photocatalytic performance of Resin–Au–Pd nanocomposite for degradation of parathion pesticide under visible light

In this work, Pd-Au nanoparticles supported on Amberlyst® resin (Pd-Au/Amberlyst®) as bimetallic photocatalyst with super adsorption performance, plasmonic effect, and fast interfacial charge migration was synthesized. The nano photocatalyst was characterized by FT-IR, ICP, XRD, FESEM, EDS mapping analysis, and TEM. Photocatalytic degradation under visible light of parathion as an organophosphorus pesticide by Pd-Au/Amberlyst® nanocomposite was studied. UV–Vis absorption spectroscopic technique studies were employed to investigate the performance of the nanocatalyst. This nanocatalyst has several fascinating advantages including easy preparation method, good catalytic activity, environmentally benign reaction conditions and was recovered with no considerable decrease in activity, it could be reused 6 times without obvious decrease in the yield of reactions.

An Electrochemical Impedance Spectroscopy Study of Hydroxide Ion Conduction in Polymer Electrolytes

Solid alkaline polymer electrolytes are important enablers for safe, lightweight, electrochemical energy storage devices. Tetraethylammonium hydroxide (TEAOH) is an OH- ion conductor, compatible with various water soluble polymers[1,2]. Polyacrylamide (PAM), a hygroscopic amorphous polymer, was combined with TEAOH to form a solid electrolyte. The resulting TEAOH-PAM electrolyte exhibited good ionic conductivity (> 10 mS cm-1) at room temperature. However, its performance can vary with the environmental relative humidity (RH). It was reported that TEAOH is prone to bond with water, forming different hydrate compounds that may impact OH- ion-conduction[3]. In addition, the role of ion content and ion motion on OH- ion-conduction in a polymer matrix needs to be further clarified by using dielectric analysis[4]. Therefore, it is important to elucidate the influence of these effects on OH- ion-conduction in the solid-state under different environmental conditions (i.e. RH, temperature). In this study, we investigated the ionic conduction mechanism at various temperatures using electrochemical impedance spectroscopy (EIS). The capacitances of the enabled solid cells and conductivities of the electrolytes were correlated to ion content and ion motion by dielectric analyses from the EIS data. The hydration structure of ions in TEAOH-PAM was quantified under three levels of RH[3]. Through analyzing these properties at elevated temperatures, an interplay of conduction mechanisms between ion transport via segmental motion of the polymer chains and OH- ion hopping was discovered (Fig. 1). High temperature studies were performed on 2D solid-state electrochemical double layer capacitors (EDLCs), leveraging the TEAOH-PAM electrolyte with vertically-oriented graphene nanosheet (VOGN). The super high rate performance of the solid-state EDLC was demonstrated at and above 100 °C. While the device operates optimally at 100 °C, it is also capable of withstanding short-term temperature exposure up to 120 °C. The excellent thermal resilience was further evidenced by the repeatable performance after subjecting to thermal cycles. From thermogravimetric analysis and Raman spectroscopy experiments at different temperatures, we found that dehydration of TEAOH-PAM is linked to rearrangement of ion conformations. This change in chemistry with higher thermal energy are key attributes responsible for the device’s temperature dependent performance. These results provide guidelines and strategies to design polymer electrolytes for high performance solid-state energy storage devices.

Study on mechanical properties of slag active powder concretethe

Concrete with high durability and green environmental protection is an important direction for future research on cement-based materials. As a kind of new building material with super high performance, reactive powder concrete (RPC) will play an important role in future construction. In this paper, slag was selected as the main cementitious material of RPC, and the influence of the content change of the admixture in RPC: steel fiber, glass fiber and polypropylene fiber on the mechanical properties of RPC was studied to analyze and select the optimal dosage of each component and take it as the reference of the optimal mixture ratio of RPC.

Efficiently multifunctional catalysts of 3D ordered meso-macroporous Ce0.3Zr0.7O2-supported PdAu@CeO2 core-shell nanoparticles for soot oxidation: Synergetic effect of Pd-Au-CeO2 ternary components

Efficiently multifunctional catalyst of PdAu@CeO2 core-shell nanoparticles supported on 3D ordered meso-macroporous Ce0.3Zr0.7O2 (PdAu@CeO2/3DOMM-CZ) was elaborately synthesized by gas bubbling-assisted membrane reduction-precipitation (GBMR/P) method. The uniform 3DOMM structure with the larger surface area improves the contact efficiency between reactants (O2, NO and soot) and catalysts, and increases the density of supported active sites. The nanostructure of AuPd (core) and CeO2 layer (shell) with optimal interface area of metal-oxides increases the surface density of active oxygen species (oxygen vacancy) for enhancing adsorption and activation of O2 and NO reactants. PdAu@CeO2/3DOMM-CZ catalyst, which takes both advantages of the good contact efficiency between reactants and catalysts by 3DOMM structure and the high density of active sites for activated reactants (O2 and NO) by PdAu@CeO2 core-shell NPs, exhibited super catalytic performance for soot oxidation under conditions of the simulated real exhaust including NO, soot, N2, O2 and H2O. For instance, its TOF value is 2.51 h−1 at 290 °C, which is more than 5-fold increase for 3DOMM-CZ oxide (0.46 h−1), and the values of T10, T50, T90 are 276, 363, 404 °C, respectively. PdAu@CeO2/3DOMM-CZ catalyst exhibits the high stability and the good tolerance property for SO2 during catalytic soot oxidation. The catalytic mechanism for soot oxidation was investigated by in-situ Raman spectra, and the synergetic effect of Pd-Au-CeO2 ternary active components can promote the rate determining step of NO oxidation to NO2. Insight into the fabrication strategy and the catalytic mechanism for soot oxidation are expected to further obtain the high-efficient catalyst in the practical applications.

High‐Fluorinated Electrolytes for Li–S Batteries

AbstractRechargeable Li–S batteries are regarded as one of the most promising next‐generation energy‐storage systems. However, the inevitable formation of Li dendrites and the shuttle effect of lithium polysulfides significantly weakens electrochemical performance, preventing its practical application. Herein, a new class of localized high‐concentration electrolyte (LHCE) enabled by adding inert fluoroalkyl ether of 1H,1H,5H‐octafluoropentyl‐1,1,2,2‐tetrafluoroethyl ether into highly‐concentrated electrolytes (HCE) lithium bis(fluorosulfonyl) imide/dimethoxyether (DME) system is reported to suppress Li dendrite formation and minimize the solubility of the high‐order polysulfides in electrolytes, thus reducing the amount of electrolyte in cells. Such a unique LHCE can achieve a high coulombic efficiency of Li plating/stripping up to 99.3% and completely suppressing the shuttling effect, thus maintaining a S cathode capacity of 775 mAh g−1 for 150 cycles with a lean electrolyte of 4.56 g A−1 h−1. The LHCE reduces the solubility of lithium polysulfides, allowing the Li/S cell to achieve super performance in a lean electrolyte. This conception of using inert diluents in a highly concentrated electrolyte can accelerate commercialization of Li–S battery technology.

When Buffett Meets Bollinger: An Integrated Approach to Fundamental and Technical Analysis

Motivated by the implication of prominent behavioral models that a joint consideration of past price changes and firm fundamentals could efficiently identify stock mispricing, we propose an integrated approach that combines fundamental and technical information. This integrated approach generates substantial economic gains, which are comparable to those of strategies double-sorted on characteristics related to high turnover and trading costs and state-of-the-art machine learning strategies in existing studies. The performance net of transaction costs is still attractive. Consistent with behavioral models, limits to arbitrage and information asymmetry play a significant role in explaining the super performance of this integrated approach.

Fabrication of UV curable coating for super hydrophobic cotton fabrics

A super hydrophobic cotton fabric was successfully prepared by a facile dip‐coating method using a synthetic fluorine‐free and UV curable super hydrophobic coating solution without additional particles. The obtained cotton fabric exhibited super hydrophobic property with a water contact angle above 159.5° and sliding angle 7.5°. Moreover, the treated cotton fabric could retain its super hydrophobic performance even after abrasion and accelerated laundering, as well as for different kinds of corrosive liquids. The coated cotton fabric was used to make up a surface tension‐driven, gravity‐assisted, floating oil–water separation device with separation efficiency above 99%. Additionally, the oil–water separation efficiency of super hydrophobic cotton fabric always was above 98% after 30 recycle times for cyclohexane–water mixture. POLYM. ENG. SCI., 59:E452–E459, 2019. © 2019 Society of Plastics Engineers

Detection of particle position from a linear interferometric out-of-focus image

A high precision method based on erosion match is proposed to extract the location coordinate of particles from a compression interferogram. With this method, particles can be positioned exactly when the overlap coefficients for that perpendicular and parallel to the fringes are less than 94.23% and 25% respectively. Super performance with the method is well confirmed by the synthetic and experiment data. Furthermore, the method can also be employed in the center detecting of complex fringe patterns for both circular and linear fringe images. The numerical and experimental results suggest that the method presented may be of considerable value to high-density spray field in accurately measuring both the particle location and its velocity.

Impulsive Control of Nonlinear Systems With Time-Varying Delay and Applications.

Impulsive control of nonlinear delay systems is studied in this paper, where the time delays addressed may be the constant delay, bounded time-varying delay, or unbounded time-varying delay. Based on the impulsive control theory and some analysis techniques, a new theoretical result for global exponential stability is derived from the impulsive control point of view. The significance of the presented result is that the stability can be achieved via the impulsive control at certain impulse points despite the existence of impulsive perturbations which causes negative effect to the control. That is, the impulsive control provides a super performance to allow the existence of impulsive perturbations. In addition, we apply the theoretical result to the problem of impulsive control of delayed neural networks. Some results for global exponential stability and synchronization control of neural networks with time delays are derived via impulsive control. Three illustrated examples are given to show the effectiveness and distinctiveness of the proposed impulsive control schemes.

Hyperbranched polymer–silver nanohybrid induce super antibacterial activity and high performance to cotton fabric

Herein we present a novel approach for synthesis, characterization and application of a benign hyperbranched polyester amide–silver nanohybrid (Ag/HBPEA). The Ag/HBPEA is developed through three distinct steps. The first step involves amidation reaction of diethanol amine and maleic anhydride to yield AB2 monomer (adduct 1). The second step comprises reaction of adduct 1 with trimethylol propane in presence of catalyst to yield HBPEA. The third step entails reduction of silver nitrate by sodium borohydride reductant to effect in situ formation of AgNPs which are stabilized by HBPEA, leading ultimately to Ag/HBPEA nanohybrid. Both Ag/HBPEA nanohybrid and HBPEA are independently applied to cotton fabrics as per the conventional pad-dry-cure technique. To this end, through investigations into the structures of Ag/HBPEA nanohybrid and HBPEA stabilizer before and after application to cotton fabric using advanced techniques emphasize the Ag/HBPEA nanohybrid as multifunctional finishing agent rather than a super antibacterial activity of the cotton fabrics after treatment with Ag/HBPEA nanohybrid speaks of this. Current research generally addresses green chemistry because treatments involved therein are based on green basics and practices.

Hydrophobic modification of SAPO-34 membranes for improvement of stability under wet condition

Abstract SAPO-34 zeolite membranes show high efficiency for CO2/CH4 separation but suffer from the reduction of separation performance when exposed to humid atmosphere. In this work, n-dodecyltrimethoxysilane (DTMS) was used to modify the hollow fibers supported SAPO-34 membranes to increase the external surface hydrophobicity and thus sustain their performance under moisture environment. The modified membranes were fully characterized. Their separation performance was extensively investigated in both dry and wet gaseous systems and compared with the un-modified ones. The un-modified SAPO-34 membrane exhibited a high separation selectivity of 160 and CO2 permeance of 1.18 × 10−6 mol·m−2·s−1·Pa−1 for separation of dry CO2/CH4 at 298 K. However, its separation selectivity declined to 0.9 and the CO2 permeance was only about 1.7 × 10−8 mol·m−2·s−1·Pa−1 for wet CO2/CH4 at same temperature. High temperature (e.g. 353 K) could reduce the effect of moisture to improve SAPO-34 separation selectivity, but further increasing temperature (e.g. 373 K) led to decrease in CO2/CH4 separation selectivity. A significant decrease of selectivity was observed at higher pressure drop. The modified SAPO-34 membrane showed decreased CO2 permeance but increased separation selectivity for dry CO2/CH4 gas mixture, and super performance for wet CO2/CH4 gas mixture due to the improved hydrophobicity of membrane surface. A separation selectivity of 65 and CO2 permeance of 4.73 × 10−8 mol·m−2·s−1·Pa−1 for wet CO2/CH4 mixture can be observed at 353 K with a pressure drop of 0.4 MPa. Furthermore, the modified membrane exhibited stable separation performance during the 120-hour test for wet CO2/CH4 mixture at 353 K. The hydrophobic modification paves a way for SAPO-34 membranes in real applications.

One-step controllable synthesis of amorphous (Ni-Fe)Sx/NiFe(OH)y hollow microtube/sphere films as superior bifunctional electrocatalysts for quasi-industrial water splitting at large-current-density

Crystalline transition-metal chalcogenides with (oxy)-hydroxides hybrids multiple nanoarchitectures are a new type of promising bifunctional electrocatalysts for electrolysis of water, but their amorphous states are scarcely studied. Herein, a facile electrodeposited approach is presented to fabricate hierarchically amorphous (Ni-Fe)Sx/NiFe(OH)y films on Nickel foam. By accurately tuning multi-components and electrochemical-parameters resulting in abundant micro-tube/sphere morphologies and phase evolution to obtain unique amorphous nano-cluster architectures, the (Ni-Fe)Sx/NiFe(OH)y catalyst performs super electrocatalytic performance, driving the current density of 100 mA·cm−2 at ultralow overpotential of 124 mV and 290 mV for hydrogen and oxygen evolution reaction in 1 M KOH solution with first-class long-term stability for at least 50 h, respectively. In addition, the bimetallic Ni-Fe sulfides and NiFe hydroxides are confirmed to be highly-intrinsic active components for HER and OER. More importantly, the (Ni-Fe)Sx/NiFe(OH)y material directly as cathode and anode electrodes, achieves 10 mA·cm−2 at low electrolytic voltage of 1.46 V in 1 M KOH, even at large current density of 1200 mA·cm-2 only needing 2.2 V as well as super-durability at 1000 mA·cm-2 for 50 h in quasi-industrial conditions. Further experimental results reveal that both temperature and appropriate alkalinity are in favour of reducing the overall hydrolytic overpotential due to accelerating sluggish thermodynamics and dynamics. Parallelly, the bifunctional (Ni-Fe)Sx/NiFe(OH)y electrode is one of the best efficient electrocatalysts in alkaline electrolyte up to now and expected for large-scale industrial water-splitting at large-current-density.

An approach to revising the climate forecast system reanalysis rainfall data in a sparsely-gauged mountain basin

Accurate spatial rainfall data are a key input parameter for distributed hydrological models and a significant contributor to hydrological model uncertainty when rain gauges are sparsely distributed, especially in complex mountain basins. The rainfall data recorded by gauge stations are considered to be real and accurate but gauged rainfall data are sometimes not representative of the rainfall spatial distribution due to a lack of stations. The Climate Forecast System Reanalysis (CFSR) product is widely used to provide the spatial variability of rainfall, especially in sparsely-gauged basins. However, the CFSR has a critical flaw of a high single-point observation error. Hence, this study developed an approach to revise the daily CFSR rainfall data by combining gauged rainfall data and considering the spatial heterogeneity of the CFSR rainfall. First, Thiessen polygons were generated to define the measurement domain of each rain gauge station. Second, spatial regression equations were developed between the CFSR rainfall data based on the size of the correlation coefficient (R), i.e., the R was ranked to determine the criteria. Third, the CFSR rainfall data in the gauged pixels were replaced by the gauged rainfall data (CFSR pixels containing one gauge station that are termed gauged pixels). Finally, the CFSR rainfall data in the non-gauged pixels was corrected based on the regression equations obtained in the second step. The upstream of the Lancang-Mekong River (transboundary river in Southeast Asia) was served as an example and three types of rainfall data (gauged, CFSR, and corrected CFSR rainfall data) were applied to establish the Soil and Water Assessment Tool (SWAT) model, which was used to simulate runoff in the upstream of the Lancang-Mekong River (UL-MR) at monthly scales. We investigated the difference in the SWAT model results among these three datasets using the relative bias (BIAS), coefficient of determination (R2), and Nash-Sutcliffe efficiency (NSE). The results indicated that the CFSR rainfall data corrected by our proposed method exhibited super performance compared to the gauged rainfall data for discharge simulations based on the SWAT model; the NSE value increased by 18.92% (from 0.74 to 0.88), the R2 value increased by 2.30% (from 0.87 to 0.89), and the BIAS value decreased by 9.48% (from 17.4% to 7.95%) in the validation period at the outlet station of the UL-MR. The proposed correction method takes into account the spatial heterogeneity of rainfall and achieves a better result for the hydrological simulation of discharge than the gauged and CFSR rainfall data, especially in complex mountain basins with sparsely distributed gauges.

Tensor-Train Fuzzy Deep Computation Model for Citywide Traffic Flow Prediction

Accuracy is extensively considered a key issue for traffic big data prediction in a vehicular cyber-physical system (VCPS). Deep learning with super performance has been successfully applied to traffic prediction for feature learning. However, uncertain traffic big data pose a remarkable challenge on current deep learning models, which work in a vector space in a deterministic manner and fail to learn the features of uncertain traffic data. This study solves the problem of citywide traffic flow prediction to satisfy the accuracy requirement of the VCPS from the perspective of users. In this study, a tensor-train fuzzy deep convolution (TFDC) approach is first proposed to satisfy the accuracy requirements of traffic flow prediction. Moreover, the Tucker deep computation (T-TFDC) approach for TFDC is proposed to satisfy the prediction accuracy requirements with low computational complexity. The TFDC model is built upon the fuzzy deep convolutional network, which uses unified tensor data representation for spatio-temporal traffic flow data. The key idea of the T-TFDC is to introduce Tucker decomposition into the TFDC model to compress parameters for traffic flow feature learning. Furthermore, learning algorithms for training TFDC and T-TFDC model parameters are devised on the basis of the back-propagation strategy. Experimental results on the TaxiBJ and BikeNYC data sets verify the effectiveness and efficiency of the proposed approaches over state-of-the-art methods.

Morphology control of α-Fe2O3 towards super electrochemistry performance.

α-Fe2O3 with various morphologies including spindle, rod, tube, disk, and ring were synthesized through controlling the H2PO4− etching process. The concentrations of H2PO4− plays an important role in controlling the morphology change of the samples. Selected adsorption of H2PO4− ions resulted in anisotropic growth. In addition, the etching of H2PO4− occurred in the center of rods which resulted in tubal α-Fe2O3. Nanodiscs were created once the etching process occurred on the wall of the tube. The electrochemical test shows that disklike samples revealed excellent specific capacitance, rate capacity and cycling stability because of relative higher surface area and pore structure. For the CO catalytic oxidation properties, spindle samples exhibited super catalytic activity.